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  • OpenGL antialiasing not working

    - by user146780
    I'v been trying to anti alias with OGL. I found a code chunk that is supposed to do this but I see no antialiasing. I also reset my settings in Nvidia Control Panel but no luck. Does this code in fact antialias the cube? GLboolean polySmooth = GL_TRUE; static void init(void) { glCullFace (GL_BACK); glEnable (GL_CULL_FACE); glBlendFunc (GL_SRC_ALPHA_SATURATE, GL_ONE); glClearColor (0.0, 0.0, 0.0, 0.0); } #define NFACE 6 #define NVERT 8 void drawCube(GLdouble x0, GLdouble x1, GLdouble y0, GLdouble y1, GLdouble z0, GLdouble z1) { static GLfloat v[8][3]; static GLfloat c[8][4] = { {0.0, 0.0, 0.0, 1.0}, {1.0, 0.0, 0.0, 1.0}, {0.0, 1.0, 0.0, 1.0}, {1.0, 1.0, 0.0, 1.0}, {0.0, 0.0, 1.0, 1.0}, {1.0, 0.0, 1.0, 1.0}, {0.0, 1.0, 1.0, 1.0}, {1.0, 1.0, 1.0, 1.0} }; /* indices of front, top, left, bottom, right, back faces */ static GLubyte indices[NFACE][4] = { {4, 5, 6, 7}, {2, 3, 7, 6}, {0, 4, 7, 3}, {0, 1, 5, 4}, {1, 5, 6, 2}, {0, 3, 2, 1} }; v[0][0] = v[3][0] = v[4][0] = v[7][0] = x0; v[1][0] = v[2][0] = v[5][0] = v[6][0] = x1; v[0][1] = v[1][1] = v[4][1] = v[5][1] = y0; v[2][1] = v[3][1] = v[6][1] = v[7][1] = y1; v[0][2] = v[1][2] = v[2][2] = v[3][2] = z0; v[4][2] = v[5][2] = v[6][2] = v[7][2] = z1; #ifdef GL_VERSION_1_1 glEnableClientState (GL_VERTEX_ARRAY); glEnableClientState (GL_COLOR_ARRAY); glVertexPointer (3, GL_FLOAT, 0, v); glColorPointer (4, GL_FLOAT, 0, c); glDrawElements(GL_QUADS, NFACE*4, GL_UNSIGNED_BYTE, indices); glDisableClientState (GL_VERTEX_ARRAY); glDisableClientState (GL_COLOR_ARRAY); #else printf ("If this is GL Version 1.0, "); printf ("vertex arrays are not supported.\n"); exit(1); #endif } /* Note: polygons must be drawn from front to back * for proper blending. */ void display(void) { if (polySmooth) { glClear (GL_COLOR_BUFFER_BIT); glEnable (GL_BLEND); glEnable (GL_POLYGON_SMOOTH); glDisable (GL_DEPTH_TEST); } else { glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glDisable (GL_BLEND); glDisable (GL_POLYGON_SMOOTH); glEnable (GL_DEPTH_TEST); } glPushMatrix (); glTranslatef (0.0, 0.0, -8.0); glRotatef (30.0, 1.0, 0.0, 0.0); glRotatef (60.0, 0.0, 1.0, 0.0); drawCube(-0.5, 0.5, -0.5, 0.5, -0.5, 0.5); glPopMatrix (); glFlush (); } void reshape(int w, int h) { glViewport(0, 0, (GLsizei) w, (GLsizei) h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(30.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } void keyboard(unsigned char key, int x, int y) { switch (key) { case `t': case `T': polySmooth = !polySmooth; glutPostRedisplay(); break; case 27: exit(0); /* Escape key */ break; default: break; } } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_ALPHA | GLUT_DEPTH); glutInitWindowSize(200, 200); glutCreateWindow(argv[0]); init (); glutReshapeFunc (reshape); glutKeyboardFunc (keyboard); glutDisplayFunc (display); glutMainLoop(); return 0; } Thanks

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  • Problem simulating HTTP POST using HttpClient

    - by user560904
    I am trying to programatically send a HTTP Post request using HttpClient to http://ojp.nationalrail.co.uk/en/s/planjourney/query but it is not liking the request I send it. I copied the headers and body from what Chrome browser sends so it is identical but it doesn't like what I send as the HTML mentions there's an error. <div class="padding"> <h1 class="sifr"><strong>Sorry</strong>, something went wrong</h1> <div class="error-message"> <div class="error-message-padding"> <h2>There is a problem with the page you are trying to access.</h2> <p>It is possible that it was either moved, it doesn't exist or we are experiencing some technical difficulties.</p> <p>We are sorry for the inconvenience.</p> </div> </div> </div> Here is my Java program which uses HttpClient: package com.tixsnif; import org.apache.http.*; import org.apache.http.client.HttpClient; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import org.apache.http.protocol.HTTP; import java.io.*; import java.util.*; import java.util.zip.GZIPInputStream; public class WebScrapingTesting { public static void main(String[] args) throws Exception { String target = "http://ojp.nationalrail.co.uk/en/s/planjourney/query"; HttpClient client = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(target); BasicNameValuePair[] params = { new BasicNameValuePair("jpState", "single"), new BasicNameValuePair("commandName", "journeyPlannerCommand"), new BasicNameValuePair("from.searchTerm", "Basingstoke"), new BasicNameValuePair("to.searchTerm", "Reading"), new BasicNameValuePair("timeOfOutwardJourney.arrivalOrDeparture", "DEPART"), new BasicNameValuePair("timeOfOutwardJourney.monthDay", "Today"), new BasicNameValuePair("timeOfOutwardJourney.hour", "10"), new BasicNameValuePair("timeOfOutwardJourney.minute", "15"), new BasicNameValuePair("timeOfReturnJourney.arrivalOrDeparture", "DEPART"), new BasicNameValuePair("timeOfReturnJourney.monthDay", "Today"), new BasicNameValuePair("timeOfReturnJourney.hour", "18"), new BasicNameValuePair("timeOfReturnJourney.minute", "15"), new BasicNameValuePair("_includeOvertakenTrains", "on"), new BasicNameValuePair("viaMode", "VIA"), new BasicNameValuePair("via.searchTerm", "Station name / code"), new BasicNameValuePair("offSetOption", "0"), new BasicNameValuePair("_reduceTransfers", "on"), new BasicNameValuePair("operatorMode", "SHOW"), new BasicNameValuePair("operator.code", ""), new BasicNameValuePair("_lookForSleeper", "on"), new BasicNameValuePair("_directTrains", "on")}; httpPost.setHeader("Host", "ojp.nationalrail.co.uk"); httpPost.setHeader("User-Agent", "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_4; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.231 Safari/534.10"); httpPost.setHeader("Accept-Encoding", "gzip,deflate,sdch"); httpPost.setHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,**/*//*;q=0.8"); httpPost.setHeader("Accept-Language", "en-us,en;q=0.8"); httpPost.setHeader("Accept-Charset", "ISO-8859-1,utf-8;q=0.7,*;q=0.7"); httpPost.setHeader("Origin", "http://www.nationalrail.co.uk/"); httpPost.setHeader("Referer", "http://www.nationalrail.co.uk/"); httpPost.setHeader("Content-Type", "application/x-www-form-urlencoded"); httpPost.setHeader("Cookie", "JSESSIONID=B2A3419B79C5D999CA4806B459675CCD.app201; Path=/"); UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(Arrays.asList(params)); urlEncodedFormEntity.setContentEncoding(HTTP.UTF_8); httpPost.setEntity(urlEncodedFormEntity); HttpResponse response = client.execute(httpPost); InputStream input = response.getEntity().getContent(); GZIPInputStream gzip = new GZIPInputStream(input); InputStreamReader isr = new InputStreamReader(gzip); BufferedReader br = new BufferedReader(isr); String line = null; while((line = br.readLine()) != null) { System.out.printf("\n%s", line); } client.getConnectionManager().shutdown(); } } I keep the JSESSION ID updated if it expires but there seems to be another problem that I cannot see. Am I missing something rather obvious? He

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  • Memory Troubles with UIImagePicker

    - by Dan Ray
    I'm building an app that has several different sections to it, all of which are pretty image-heavy. It ties in with my client's website and they're a "high-design" type outfit. One piece of the app is images uploaded from the camera or the library, and a tableview that shows a grid of thumbnails. Pretty reliably, when I'm dealing with the camera version of UIImagePickerControl, I get hit for low memory. If I bounce around that part of the app for a while, I occasionally and non-repeatably crash with "status:10 (SIGBUS)" in the debugger. On low memory warning, my root view controller for that aspect of the app goes to my data management singleton, cruises through the arrays of cached data, and kills the biggest piece, the image associated with each entry. Thusly: - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Low Memory Warning" message:@"Cleaning out events data" delegate:nil cancelButtonTitle:@"All right then." otherButtonTitles:nil]; [alert show]; [alert release]; NSInteger spaceSaved; DataManager *data = [DataManager sharedDataManager]; for (Event *event in data.eventList) { spaceSaved += [(NSData *)UIImagePNGRepresentation(event.image) length]; event.image = nil; spaceSaved -= [(NSData *)UIImagePNGRepresentation(event.image) length]; } NSString *titleString = [NSString stringWithFormat:@"Saved %d on event images", spaceSaved]; for (WondrMark *mark in data.wondrMarks) { spaceSaved += [(NSData *)UIImagePNGRepresentation(mark.image) length]; mark.image = nil; spaceSaved -= [(NSData *)UIImagePNGRepresentation(mark.image) length]; } NSString *messageString = [NSString stringWithFormat:@"And total %d on event and mark images", spaceSaved]; NSLog(@"%@ - %@", titleString, messageString); // Relinquish ownership any cached data, images, etc that aren't in use. } As you can see, I'm making a (poor) attempt to eyeball the memory space I'm freeing up. I know it's not telling me about the actual memory footprint of the UIImages themselves, but it gives me SOME numbers at least, so I can see that SOMETHING'S happening. (Sorry for the hamfisted way I build that NSLog message too--I was going to fire another UIAlertView, but realized it'd be more useful to log it.) Pretty reliably, after toodling around in the image portion of the app for a while, I'll pull up the camera interface and get the low memory UIAlertView like three or four times in quick succession. Here's the NSLog output from the last time I saw it: 2010-05-27 08:55:02.659 EverWondr[7974:207] Saved 109591 on event images - And total 1419756 on event and mark images wait_fences: failed to receive reply: 10004003 2010-05-27 08:55:08.759 EverWondr[7974:207] Saved 4 on event images - And total 392695 on event and mark images 2010-05-27 08:55:14.865 EverWondr[7974:207] Saved 4 on event images - And total 873419 on event and mark images 2010-05-27 08:55:14.969 EverWondr[7974:207] Saved 4 on event images - And total 4 on event and mark images 2010-05-27 08:55:15.064 EverWondr[7974:207] Saved 4 on event images - And total 4 on event and mark images And then pretty soon after that we get our SIGBUS exit. So that's the situation. Now my specific questions: THE time I see this happening is when the UIPickerView's camera iris shuts. I click the button to take the picture, it does the "click" animation, and Instruments shows my memory footprint going from about 10mb to about 25mb, and sitting there until the image is delivered to my UIViewController, where usage drops back to 10 or 11mb again. If we make it through that without a memory warning, we're golden, but most likely we don't. Anything I can do to make that not be so expensive? Second, I have NSZombies enabled. Am I understanding correctly that that's actually preventing memory from being freed? Am I subjecting my app to an unfair test environment? Third, is there some way to programmatically get my memory usage? Or at least the usage for a UIImage object? I've scoured the docs and don't see anything about that.

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  • How to have two UIPickerViews together in one ViewController?

    - by 0SX
    I'm trying to put 2 UIPickerViews together in one ViewController. Each UIPickerView has different data arrays. I'm using interface builder to link the pickers up. I know I'll have to use separate delegates and dataSources but I can't seem to hook everything up with interface builder correctly. Here's all my code: pickerTesting.h #import <UIKit/UIKit.h> #import "picker2DataSource.h" @interface pickerTestingViewController : UIViewController <UIPickerViewDelegate, UIPickerViewDataSource>{ IBOutlet UIPickerView *picker; IBOutlet UIPickerView *picker2; NSMutableArray *pickerViewArray; } @property (nonatomic, retain) IBOutlet UIPickerView *picker; @property (nonatomic, retain) IBOutlet UIPickerView *picker2; @property (nonatomic, retain) NSMutableArray *pickerViewArray; @end pickerTesting.m #import "pickerTestingViewController.h" @implementation pickerTestingViewController @synthesize picker, picker2, pickerViewArray; - (void)viewDidLoad { [super viewDidLoad]; pickerViewArray = [[NSMutableArray alloc] init]; [pickerViewArray addObject:@" 100 "]; [pickerViewArray addObject:@" 200 "]; [pickerViewArray addObject:@" 400 "]; [pickerViewArray addObject:@" 600 "]; [pickerViewArray addObject:@" 1000 "]; [picker selectRow:1 inComponent:0 animated:NO]; picker2.delegate = self; picker2.dataSource = self; } - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)picker; { return 1; } - (void)pickerView:(UIPickerView *)picker didSelectRow:(NSInteger)row inComponent:(NSInteger)component { } - (NSInteger)pickerView:(UIPickerView *)picker numberOfRowsInComponent:(NSInteger)component; { return [pickerViewArray count]; } - (NSString *)pickerView:(UIPickerView *)picker titleForRow:(NSInteger)row forComponent:(NSInteger)component; { return [pickerViewArray objectAtIndex:row]; } - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } - (void)viewDidUnload { // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; } - (void)dealloc { [super dealloc]; } @end And I have a separate class for the other datasource. picker2DataSource.h @interface picker2DataSource : NSObject <UIPickerViewDataSource, UIPickerViewDelegate> { NSMutableArray *customPickerArray; } @property (nonatomic, retain) NSMutableArray *customPickerArray; @end picker2DataSource.m #import "picker2DataSource.h" @implementation picker2DataSource @synthesize customPickerArray; - (id)init { // use predetermined frame size self = [super init]; if (self) { customPickerArray = [[NSMutableArray alloc] init]; [customPickerArray addObject:@" a "]; [customPickerArray addObject:@" b "]; [customPickerArray addObject:@" c "]; [customPickerArray addObject:@" d "]; [customPickerArray addObject:@" e "]; } return self; } - (void)dealloc { [customPickerArray release]; [super dealloc]; } - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)picker2; { return 1; } - (void)pickerView:(UIPickerView *)picker2 didSelectRow:(NSInteger)row inComponent:(NSInteger)component { } - (NSInteger)pickerView:(UIPickerView *)picker2 numberOfRowsInComponent:(NSInteger)component; { return [customPickerArray count]; } - (NSString *)pickerView:(UIPickerView *)picker2 titleForRow:(NSInteger)row forComponent:(NSInteger)component; { return [customPickerArray objectAtIndex:row]; } @end Any help or code examples would be great. Thanks.

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  • Correct XML serialization and deserialization of "mixed" types in .NET

    - by Stefan
    My current task involves writing a class library for processing HL7 CDA files. These HL7 CDA files are XML files with a defined XML schema, so I used xsd.exe to generate .NET classes for XML serialization and deserialization. The XML Schema contains various types which contain the mixed="true" attribute, specifying that an XML node of this type may contain normal text mixed with other XML nodes. The relevant part of the XML schema for one of these types looks like this: <xs:complexType name="StrucDoc.Paragraph" mixed="true"> <xs:sequence> <xs:element name="caption" type="StrucDoc.Caption" minOccurs="0"/> <xs:choice minOccurs="0" maxOccurs="unbounded"> <xs:element name="br" type="StrucDoc.Br"/> <xs:element name="sub" type="StrucDoc.Sub"/> <xs:element name="sup" type="StrucDoc.Sup"/> <!-- ...other possible nodes... --> </xs:choice> </xs:sequence> <xs:attribute name="ID" type="xs:ID"/> <!-- ...other attributes... --> </xs:complexType> The generated code for this type looks like this: /// <remarks/> [System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "2.0.50727.3038")] [System.SerializableAttribute()] [System.Diagnostics.DebuggerStepThroughAttribute()] [System.ComponentModel.DesignerCategoryAttribute("code")] [System.Xml.Serialization.XmlTypeAttribute(TypeName="StrucDoc.Paragraph", Namespace="urn:hl7-org:v3")] public partial class StrucDocParagraph { private StrucDocCaption captionField; private object[] itemsField; private string[] textField; private string idField; // ...fields for other attributes... /// <remarks/> public StrucDocCaption caption { get { return this.captionField; } set { this.captionField = value; } } /// <remarks/> [System.Xml.Serialization.XmlElementAttribute("br", typeof(StrucDocBr))] [System.Xml.Serialization.XmlElementAttribute("sub", typeof(StrucDocSub))] [System.Xml.Serialization.XmlElementAttribute("sup", typeof(StrucDocSup))] // ...other possible nodes... public object[] Items { get { return this.itemsField; } set { this.itemsField = value; } } /// <remarks/> [System.Xml.Serialization.XmlTextAttribute()] public string[] Text { get { return this.textField; } set { this.textField = value; } } /// <remarks/> [System.Xml.Serialization.XmlAttributeAttribute(DataType="ID")] public string ID { get { return this.idField; } set { this.idField = value; } } // ...properties for other attributes... } If I deserialize an XML element where the paragraph node looks like this: <paragraph>first line<br /><br />third line</paragraph> The result is that the item and text arrays are read like this: itemsField = new object[] { new StrucDocBr(), new StrucDocBr(), }; textField = new string[] { "first line", "third line", }; From this there is no possible way to determine the exact order of the text and the other nodes. If I serialize this again, the result looks exactly like this: <paragraph> <br /> <br />first linethird line </paragraph> The default serializer just serializes the items first and then the text. I tried implementing IXmlSerializable on the StrucDocParagraph class so that I could control the deserialization and serialization of the content, but it's rather complex since there are so many classes involved and I didn't come to a solution yet because I don't know if the effort pays off. Is there some kind of easy workaround to this problem, or is it even possible by doing custom serialization via IXmlSerializable? Or should I just use XmlDocument or XmlReader/XmlWriter to process these documents?

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  • Adding sections to a plist for Xcode for use in Cocoa touch Table View

    - by Steve
    I am a beginning iPhone SDK programmer. I built a simple practice application I am trying to use to learn more about table views. It's an app that loads football teams from a plist and displays them in a table view with their stadium name and logo. Tapping the team goes to a detail view for that team. I am trying to understand how to add sections to this, so that I might have a couple of teams in one section and others in another section, etc. I would assume I need to both re-structure my plist and change the code to read arrays from the different levels of the plist? To begin, I had a plist with the root array consisting of 3 dictionaries, one for each team. Each dictionary had 3 keys, "name" "stadium" and "logo". This works fine. I am loading it via: NSString *path = [[NSBundle mainBundle] pathForResource:@"teams" ofType:@"plist"]; teams = [[NSMutableArray alloc] initWithContentsOfFile:path]; and then // Configure the cell. NSDictionary *team = [teams objectAtIndex:indexPath.row]; cell.textLabel.text = [team objectForKey:@"name"]; NSString *imgPath = [team valueForKey:@"logo"]; cell.imageView.image = [UIImage imageNamed:imgPath]; cell.detailTextLabel.text =[team objectForKey:@"stadium"]; return cell; No problem. But now I wanted the sections, so I changed my plist to: <array> <dict> <key>teams 1</key> <array> <dict> <key>name</key> <string>Packers</string> <key>stadium</key> <string>Lambeau Field</string> <key>logo</key> <string>packers.jpg</string> </dict> <dict> <key>name</key> <string>Jets</string> <key>stadium</key> <string>Giants Stadium</string> <key>logo</key> <string>jets_logo.jpg</string> </dict> </array> </dict> <dict> <key>teams 2</key> <array> <dict> <key>name</key> <string>Cincinnati Bengals</string> <key>stadium</key> <string>Paul Brown Stadium</string> <key>logo</key> <string>bengals.jpg</string> </dict> </array> </dict> And I am unsure how to modify the viewDidLoad to assign the sections to one NSArray and the teams "level" to another array.

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  • Android: preferences not being stored automatically

    - by Vitaly
    I'm trying to use preference screen. I'm following all steps from online tutorial (once I couldn't get it working, I found other tutorials, and steps seem to be fine). I get to preferences screen, edit values, return to calling activity (via hardware return button). In DDMS perspective FileExplorer shows package_name_preferences.xml file with preferences that should be stored. It contains: <?xml version='1.0' encoding='utf-8' standalone='yes' ?> <map> <string name="false">kg</string> </map> while I expect (data line only shown). <string name="weight">kg</string> Also, if I go change only 1 preference, the same value changes, not a new row is created. I'm just tempted to write my own preference classes that would store data in files or DB, but I know that preferences should work, it just doesn't save properly my stuff. Edit Tutorials used: Main Tutorial - Was using this as a base, simplified, as I needed only 3 listPreferences so far. Another One - Used this one back when first installed android, so referred to this one for its section on preferences Code: (Screen loads, so I'm not showing Manifest) public class MyPrefs extends PreferenceActivity { @Override public void onCreate(Bundle bundle) { super.onCreate(bundle); addPreferencesFromResource(R.xml.my_prefs); } } my_prefs.xml <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"> <PreferenceCategory android:title="Value Settings"> <ListPreference android:title="Distance" android:summary="Metric (Kilometer) vs Imperial (Imperial)" android:defaultValue="km" android:key="@+id/distanceMesurement" android:entries="@array/distance" android:entryValues="@array/distance_values"/> <ListPreference android:title="Weight" android:summary="Metric (Kilogram) vs Imperial (Pound)" android:defaultValue="kg" android:key="@+id/weightMesurement" android:entries="@array/weight" android:entryValues="@array/weight_values"/> </PreferenceCategory> </PreferenceScreen> calling MyPrefs from MainScreen Intent i = new Intent(MainScreen.this, MyPrefs.class); startActivity(i); arrays.xml <resources> <string-array name="weight"> <item name="kg">Kilogram (kg)</item> <item name="lb">Pound (lb)</item> </string-array> <string-array name="weight_values"> <item name="kg">kg</item> <item name="lb">lb</item> </string-array> <string-array name="distance"> <item name="km">Kilometer (km)</item> <item name="mi">Mile (mi)</item> </string-array> <string-array name="distance_values"> <item name="km">km</item> <item name="mi">mi</item> </string-array> </resources>

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  • Managing highly repetitive code and documentation in Java

    - by polygenelubricants
    Highly repetitive code is generally a bad thing, and there are design patterns that can help minimize this. However, sometimes it's simply inevitable due to the constraints of the language itself. Take the following example from java.util.Arrays: /** * Assigns the specified long value to each element of the specified * range of the specified array of longs. The range to be filled * extends from index <tt>fromIndex</tt>, inclusive, to index * <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the * range to be filled is empty.) * * @param a the array to be filled * @param fromIndex the index of the first element (inclusive) to be * filled with the specified value * @param toIndex the index of the last element (exclusive) to be * filled with the specified value * @param val the value to be stored in all elements of the array * @throws IllegalArgumentException if <tt>fromIndex &gt; toIndex</tt> * @throws ArrayIndexOutOfBoundsException if <tt>fromIndex &lt; 0</tt> or * <tt>toIndex &gt; a.length</tt> */ public static void fill(long[] a, int fromIndex, int toIndex, long val) { rangeCheck(a.length, fromIndex, toIndex); for (int i=fromIndex; i<toIndex; i++) a[i] = val; } The above snippet appears in the source code 8 times, with very little variation in the documentation/method signature but exactly the same method body, one for each of the root array types int[], short[], char[], byte[], boolean[], double[], float[], and Object[]. I believe that unless one resorts to reflection (which is an entirely different subject in itself), this repetition is inevitable. I understand that as a utility class, such high concentration of repetitive Java code is highly atypical, but even with the best practice, repetition does happen! Refactoring doesn't always work because it's not always possible (the obvious case is when the repetition is in the documentation). Obviously maintaining this source code is a nightmare. A slight typo in the documentation, or a minor bug in the implementation, is multiplied by however many repetitions was made. In fact, the best example happens to involve this exact class: Google Research Blog - Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken (by Joshua Bloch, Software Engineer) The bug is a surprisingly subtle one, occurring in what many thought to be just a simple and straightforward algorithm. // int mid =(low + high) / 2; // the bug int mid = (low + high) >>> 1; // the fix The above line appears 11 times in the source code! So my questions are: How are these kinds of repetitive Java code/documentation handled in practice? How are they developed, maintained, and tested? Do you start with "the original", and make it as mature as possible, and then copy and paste as necessary and hope you didn't make a mistake? And if you did make a mistake in the original, then just fix it everywhere, unless you're comfortable with deleting the copies and repeating the whole replication process? And you apply this same process for the testing code as well? Would Java benefit from some sort of limited-use source code preprocessing for this kind of thing? Perhaps Sun has their own preprocessor to help write, maintain, document and test these kind of repetitive library code? A comment requested another example, so I pulled this one from Google Collections: com.google.common.base.Predicates lines 276-310 (AndPredicate) vs lines 312-346 (OrPredicate). The source for these two classes are identical, except for: AndPredicate vs OrPredicate (each appears 5 times in its class) "And(" vs Or(" (in the respective toString() methods) #and vs #or (in the @see Javadoc comments) true vs false (in apply; ! can be rewritten out of the expression) -1 /* all bits on */ vs 0 /* all bits off */ in hashCode() &= vs |= in hashCode()

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  • Need help looping through text file in Objective-C and looping through multidimensional array of dat

    - by Fulvio
    I have a question regarding an iPhone game I'm developing. At the moment, below is the code I'm using to currently I loop through my multidimensional array and position bricks accordingly on my scene. Instead of having multiple two dimensional arrays within my code as per the following (gameLevel1). Ideally, I'd like to read from a text file within my project and loop through the values in that instead. Please take into account that I'd like to have more than one level within my game (possibly 20) so my text file would have to have some sort of separator line item to determine what level I want to render. I was then thinking of having some sort of method that I call and that method would take the level number I'm interested in rendering. e.g. Method to call level based on separator? -(void)renderLevel:(NSString) levelNumber; e.g. Text file example? #LEVEL_ONE# 0,0,0,0,0,0,0,0,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,0,0,0,0,0,0,0,0 #LEVEL_TWO# 1,0,0,0,0,0,0,0,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 0,1,1,1,1,1,1,1,0 1,1,1,1,1,1,1,1,1 0,1,1,1,1,1,1,1,0 1,1,1,1,1,1,1,1,1 0,1,1,1,1,1,1,1,0 1,1,1,1,1,1,1,1,1 0,1,1,1,1,1,1,1,0 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,0,0,0,0,0,0,0,1 Code that I'm currently using: int gameLevel[17][9] = { { 0,0,0,0,0,0,0,0,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,0,0,0,0,0,0,0,0 } }; for (int row=0; row < 17; row++) { for (int col=0; col < 9; col++) { thisBrickValue = gameLevel[row][col]; xOffset = 35 * floor(col); yOffset = 22 * floor(row); switch (thisBrickValue) { case 0: brick = [[CCSprite spriteWithFile:@"block0.png"] autorelease]; break; case 1: brick = [[CCSprite spriteWithFile:@"block1.png"] autorelease]; break; } brick.position = ccp(xOffset, yOffset); [self addChild:brick]; } }

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  • Problem with memset after an instance of a user defined class is created and a file is opened

    - by Liberalkid
    I'm having a weird problem with memset, that was something to do with a class I'm creating before it and a file I'm opening in the constructor. The class I'm working with normally reads in an array and transforms it into another array, but that's not important. The class I'm working with is: #include <vector> #include <algorithm> using namespace std; class PreProcess { public: PreProcess(char* fileName,char* outFileName); void SortedOrder(); private: vector< vector<double > > matrix; void SortRow(vector<double> &row); char* newFileName; vector< pair<double,int> > rowSorted; }; The other functions aren't important, because I've stopped calling them and the problem persists. Essentially I've narrowed it down to my constructor: PreProcess::PreProcess(char* fileName,char* outFileName):newFileName(outFileName){ ifstream input(fileName); input.close(); //this statement is inconsequential } I also read in the file in my constructor, but I've found that the problem persists if I don't read in the matrix and just open the file. Essentially I've narrowed it down to if I comment out those two lines the memset works properly, otherwise it doesn't. Now to the context of the problem I'm having with it: I wrote my own simple wrapper class for matrices. It doesn't have much functionality, I just need 2D arrays in the next part of my project and having a class handle everything makes more sense to me. The header file: #include <iostream> using namespace std; class Matrix{ public: Matrix(int r,int c); int &operator()(int i,int j) {//I know I should check my bounds here return matrix[i*columns+j]; } ~Matrix(); const void Display(); private: int *matrix; const int rows; const int columns; }; Driver: #include "Matrix.h" #include <string> using namespace std; Matrix::Matrix(int r,int c):rows(r),columns(c) { matrix=new int[rows*columns]; memset(matrix,0,sizeof(matrix)); } const void Matrix::Display(){ for(int i=0;i<rows;i++){ for(int j=0;j<columns;j++) cout << (*this)(i,j) << " "; cout << endl; } } Matrix::~Matrix() { delete matrix; } My main program runs: PreProcess test1(argv[1],argv[2]); //test1.SortedOrder(); Matrix test(10,10); test.Display(); And when I run this with the input line uncommented I get: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1371727776 32698 -1 0 0 0 0 0 6332656 0 -1 -1 0 0 6332672 0 0 0 0 0 0 0 0 0 0 0 0 0 -1371732704 32698 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I really don't have a clue what's going on in memory to cause this, on a side note if I replace memset with: for(int i=0;i<rows*columns;i++) *(matrix+i) &= 0x0; Then it works perfectly, it also works if I don't open the file. If it helps I'm running GCC 64-bit version 4.2.4 on Ubuntu.I assume there's some functionality of memset that I'm not properly understanding.

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  • How do I display a Wicket Datatable, sorted by a specific column by default?

    - by David
    Hello everyone! I have a question regarding Wicket's Datatable. I am currently using DataTable to display a few columns of data. My table is set up as follows: DataTable<Column> dataTable = new DataTable<Column>("columnsTable", columns, provider, maxRowsPerPage) { @Override protected Item<Column> newRowItem(String id, int index, IModel<Column> model) { return new OddEvenItem<Column>(id, index, model); } }; The columns look like so: columns[0] = new PropertyColumn<Column>(new Model<String>("Description"), "description", "description"); columns[1] = new PropertyColumn<Column>(new Model<String>("Logic"), "columnLogic"); columns[2] = new PropertyColumn<Column>(new Model<String>("Type"), "dataType", "dataType"); Here is my column data provider: public class ColumnSortableDataProvider extends SortableDataProvider<Column> { private static final long serialVersionUID = 1L; private List<Column> list = null; public ColumnSortableDataProvider(Table table) { this.list = Arrays.asList(table.getColumns().toArray(new Column[0])); } public ColumnSortableDataProvider(List<Column> list) { this.list = list; } @Override public Iterator<? extends Column> iterator(int first, int count) { /* first - first row of data count - minimum number of elements to retrieve So this method returns an iterator capable of iterating over {first, first+count} items */ Iterator<Column> iterator = null; try { if(getSort() != null) { Collections.sort(list, new Comparator<Column>() { private static final long serialVersionUID = 1L; @Override public int compare(Column c1, Column c2) { int result=1; PropertyModel<Comparable> model1= new PropertyModel<Comparable>(c1, getSort().getProperty()); PropertyModel<Comparable> model2= new PropertyModel<Comparable>(c2, getSort().getProperty()); if(model1.getObject() == null && model2.getObject() == null) result = 0; else if(model1.getObject() == null) result = 1; else if(model2.getObject() == null) result = -1; else result = ((Comparable)model1.getObject()).compareTo(model2.getObject()); result = getSort().isAscending() ? result : -result; return result; } }); } if (list.size() > (first+count)) iterator = list.subList(first, first+count).iterator(); else iterator = list.iterator(); } catch (Exception e) { e.printStackTrace(); } return iterator; } Sorting by clicking a column works perfectly, but I would like the table to initially be sorted, by default, by the Description column. I am at a loss to do this. If you need to see some other code, please let me know. Thank you in advance!!! - D

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  • Getting timing consistency in Linux

    - by Jim Hunziker
    I can't seem to get a simple program (with lots of memory access) to achieve consistent timing in Linux. I'm using a 2.6 kernel, and the program is being run on a dual-core processor with realtime priority. I'm trying to disable cache effects by declaring the memory arrays as volatile. Below are the results and the program. What are some possible sources of the outliers? Results: Number of trials: 100 Range: 0.021732s to 0.085596s Average Time: 0.058094s Standard Deviation: 0.006944s Extreme Outliers (2 SDs away from mean): 7 Average Time, excluding extreme outliers: 0.059273s Program: #include <stdio.h> #include <stdlib.h> #include <math.h> #include <sched.h> #include <sys/time.h> #define NUM_POINTS 5000000 #define REPS 100 unsigned long long getTimestamp() { unsigned long long usecCount; struct timeval timeVal; gettimeofday(&timeVal, 0); usecCount = timeVal.tv_sec * (unsigned long long) 1000000; usecCount += timeVal.tv_usec; return (usecCount); } double convertTimestampToSecs(unsigned long long timestamp) { return (timestamp / (double) 1000000); } int main(int argc, char* argv[]) { unsigned long long start, stop; double times[REPS]; double sum = 0; double scale, avg, newavg, median; double stddev = 0; double maxval = -1.0, minval = 1000000.0; int i, j, freq, count; int outliers = 0; struct sched_param sparam; sched_getparam(getpid(), &sparam); sparam.sched_priority = sched_get_priority_max(SCHED_FIFO); sched_setscheduler(getpid(), SCHED_FIFO, &sparam); volatile float* data; volatile float* results; data = calloc(NUM_POINTS, sizeof(float)); results = calloc(NUM_POINTS, sizeof(float)); for (i = 0; i < REPS; ++i) { start = getTimestamp(); for (j = 0; j < NUM_POINTS; ++j) { results[j] = data[j]; } stop = getTimestamp(); times[i] = convertTimestampToSecs(stop-start); } free(data); free(results); for (i = 0; i < REPS; i++) { sum += times[i]; if (times[i] > maxval) maxval = times[i]; if (times[i] < minval) minval = times[i]; } avg = sum/REPS; for (i = 0; i < REPS; i++) stddev += (times[i] - avg)*(times[i] - avg); stddev /= REPS; stddev = sqrt(stddev); for (i = 0; i < REPS; i++) { if (times[i] > avg + 2*stddev || times[i] < avg - 2*stddev) { sum -= times[i]; outliers++; } } newavg = sum/(REPS-outliers); printf("Number of trials: %d\n", REPS); printf("Range: %fs to %fs\n", minval, maxval); printf("Average Time: %fs\n", avg); printf("Standard Deviation: %fs\n", stddev); printf("Extreme Outliers (2 SDs away from mean): %d\n", outliers); printf("Average Time, excluding extreme outliers: %fs\n", newavg); return 0; }

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  • iPhone: Repeating Rows in Each Section of Grouped UITableview

    - by Rank Beginner
    I'm trying to learn how to use the UITableView in conjunction with a SQLite back end. My issue is that I've gotten the table to populate with the records from the database, however I'm having a problem with the section titles. I am not able to figure out the proper set up for this, and I'm repeating all tasks under each section. The table looks like this. The groups field is where I'm trying to pull the section title from. TaskID groups TaskName sched lastCompleted nextCompleted success 1 Household laundry 3 03/19/2010 03/22/2010 y 1 Automotive Change oil 3 03/20/2010 03/23/2010 y In my viewDidLoad Method, I create an array from each column in the table like below. //Create and initialize arrays from table columns //______________________________________________________________________________________ ids =[[NSMutableArray alloc] init]; tasks =[[NSMutableArray alloc] init]; sched =[[NSMutableArray alloc] init]; lastComplete =[[NSMutableArray alloc] init]; nextComplete =[[NSMutableArray alloc] init]; weight =[[NSMutableArray alloc] init]; success =[[NSMutableArray alloc] init]; group =[[NSMutableArray alloc] init]; // Bind them to the data //______________________________________________________________________________________ NSString *query = [NSString stringWithFormat:@"SELECT * FROM Tasks ORDER BY nextComplete "]; sqlite3_stmt *statement; if (sqlite3_prepare_v2( database, [query UTF8String], -1, &statement, nil) == SQLITE_OK) { while (sqlite3_step(statement) == SQLITE_ROW) { [ids addObject:[NSString stringWithFormat:@"%i",(int*) sqlite3_column_int(statement, 0)]]; [group addObject:[NSString stringWithFormat:@"%s",(char*) sqlite3_column_text(statement, 1)]]; [tasks addObject:[NSString stringWithFormat:@"%s",(char*) sqlite3_column_text(statement, 2)]]; [sched addObject:[NSString stringWithFormat:@"%i",(int*) sqlite3_column_int(statement, 3)]]; [lastComplete addObject:[NSString stringWithFormat:@"%s",(char*) sqlite3_column_text(statement, 4)]]; [nextComplete addObject:[NSString stringWithFormat:@"%s",(char*) sqlite3_column_text(statement, 5)]]; [success addObject:[NSString stringWithFormat:@"%s",(char*) sqlite3_column_text(statement, 6)]]; [weight addObject:[NSString stringWithFormat:@"%i",(int*) sqlite3_column_int(statement, 7)]]; } sqlite3_finalize(statement); } In the table method:cellForRowAtIndexPath, I create controls on the fly and set their text properties to objects in the array. Below is a sample, I can provide more but am already working on a book here... :) /create the task label NSString *tmpMessage; tmpMessage = [NSString stringWithFormat:@"%@ every %@ days, for %@ points",[tasks objectAtIndex:indexPath.row],[sched objectAtIndex:indexPath.row],[weight objectAtIndex:indexPath.row]]; CGRect schedLabelRect = CGRectMake(0, 0, 250, 15); UILabel *lblSched = [[UILabel alloc] initWithFrame:schedLabelRect]; lblSched.textAlignment = UITextAlignmentLeft; lblSched.text = tmpMessage; lblSched.font = [UIFont boldSystemFontOfSize:10]; [cell.contentView addSubview: lblSched]; [lblSched release]; My numberOfSectionsInTableView method looks like this // Figure out how many sections there are by a distinct count of the groups field // The groups are entered by user when creating tasks //______________________________________________________________________________________ NSString *groupquery = [NSString stringWithFormat:@"SELECT COUNT(DISTINCT groups) as Sum FROM Tasks"]; int sum; sqlite3_stmt *statement; if (sqlite3_prepare_v2( database, [groupquery UTF8String], -1, &statement, nil) == SQLITE_OK) { while (sqlite3_step(statement) == SQLITE_ROW) { sum = sqlite3_column_int(statement, 0); } sqlite3_finalize(statement); } if (sum=0) { return 1; } return 2; } I know I'm going wrong here but this is all that's in my numberOfRowsInSection method return [ids count];

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  • DataTable to JSON

    - by Joel Coehoorn
    I recently needed to serialize a datatable to JSON. Where I'm at we're still on .Net 2.0, so I can't use the JSON serializer in .Net 3.5. I figured this must have been done before, so I went looking online and found a number of different options. Some of them depend on an additional library, which I would have a hard time pushing through here. Others require first converting to List<Dictionary<>>, which seemed a little awkward and needless. Another treated all values like a string. For one reason or another I couldn't really get behind any of them, so I decided to roll my own, which is posted below. As you can see from reading the //TODO comments, it's incomplete in a few places. This code is already in production here, so it does "work" in the basic sense. The places where it's incomplete are places where we know our production data won't currently hit it (no timespans or byte arrays in the db). The reason I'm posting here is that I feel like this can be a little better, and I'd like help finishing and improving this code. Any input welcome. public static class JSONHelper { public static string FromDataTable(DataTable dt) { string rowDelimiter = ""; StringBuilder result = new StringBuilder("["); foreach (DataRow row in dt.Rows) { result.Append(rowDelimiter); result.Append(FromDataRow(row)); rowDelimiter = ","; } result.Append("]"); return result.ToString(); } public static string FromDataRow(DataRow row) { DataColumnCollection cols = row.Table.Columns; string colDelimiter = ""; StringBuilder result = new StringBuilder("{"); for (int i = 0; i < cols.Count; i++) { // use index rather than foreach, so we can use the index for both the row and cols collection result.Append(colDelimiter).Append("\"") .Append(cols[i].ColumnName).Append("\":") .Append(JSONValueFromDataRowObject(row[i], cols[i].DataType)); colDelimiter = ","; } result.Append("}"); return result.ToString(); } // possible types: // http://msdn.microsoft.com/en-us/library/system.data.datacolumn.datatype(VS.80).aspx private static Type[] numeric = new Type[] {typeof(byte), typeof(decimal), typeof(double), typeof(Int16), typeof(Int32), typeof(SByte), typeof(Single), typeof(UInt16), typeof(UInt32), typeof(UInt64)}; // I don't want to rebuild this value for every date cell in the table private static long EpochTicks = new DateTime(1970, 1, 1).Ticks; private static string JSONValueFromDataRowObject(object value, Type DataType) { // null if (value == DBNull.Value) return "null"; // numeric if (Array.IndexOf(numeric, DataType) > -1) return value.ToString(); // TODO: eventually want to use a stricter format // boolean if (DataType == typeof(bool)) return ((bool)value) ? "true" : "false"; // date -- see http://weblogs.asp.net/bleroy/archive/2008/01/18/dates-and-json.aspx if (DataType == typeof(DateTime)) return "\"\\/Date(" + new TimeSpan(((DateTime)value).ToUniversalTime().Ticks - EpochTicks).TotalMilliseconds.ToString() + ")\\/\""; // TODO: add Timespan support // TODO: add Byte[] support //TODO: this would be _much_ faster with a state machine // string/char return "\"" + value.ToString().Replace(@"\", @"\\").Replace(Environment.NewLine, @"\n").Replace("\"", @"\""") + "\""; } }

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  • Setting value for autocomplete search field linked to Google Places API

    - by user1653350
    I have a web page where people will be able to enter multiple destinations. When they state they want to enter a new destination, the current field values are stored in arrays. If they choose to go back to a previous destination, the relevant values are reinserted into the form fields. I am using the search field linked to autocomplete as the visible display of the destination. When I attempt to put a value into the linked search field, the value is presented as if it is a placeholder instead of a value. Enter the field and the value is removed by the onFocus() event of the Google Places autocomplete add-in. How can I reinsert the value and have it recognised as a value instead of placeholder. field definition in the form <label for="GoogleDestSrch" class="inputText">Destination: <span id="DestinationDisplay2">1</span> <span class="required"><font size="5"> * </font></span></label> <input id="GoogleDestSrch" type="text" size="50" placeholder="Please enter your destination" /> initialise code for Google Places API listener var input = document.getElementById('GoogleDestSrch'); var autocomplete = new google.maps.places.Autocomplete(input); google.maps.event.addListener(autocomplete, 'place_changed', function() { fillInAddress(); }); attempting to reinsert value into search field when prior destination reloaded form.GoogleDestSrch.value = GoogleDestSrch[index]; Issue With Google Places <script language="JavaScript" type="text/javascript"> function GotoDestination(index) { var domove = true; if (index == 0) { index = lastIndex + 1; } else { if (index == -1) { index = lastIndex - 1; if (index == 0) { index = 1; domove = false; } } } if (domove) { if (index != lastIndex) { var doc = window.document; var pdbutton = doc.getElementById("pdbutton"); var pdbutton1 = doc.getElementById("pdbutton1"); if ((index > lastIndex)) { // move to next destination saveDataF(lastIndex); loadDataF(index); lastIndex = index; } else if (index <= lastIndex) { // move to previous destination saveDataF(lastIndex); loadDataF(index); lastIndex = index; } } } } var input; var autocomplete; // fill in the Google metadata when a destination is selected function fillInAddress() { var strFullValue = ''; var strFullGeoValue = ''; var place = autocomplete.getPlace(); document.getElementById("GoogleType").value = place.types[0]; } function saveDataF(index) { var fieldValue; var blankSearch = "Please enter"; // placeholder text for Google Places fieldValue = document.getElementById("GoogleDestSrch").value; if (fieldValue.indexOf(blankSearch) > -1) { fieldValue = ""; } GoogleDestSrch[index] = fieldValue; } function loadDataF(index) { if ((GoogleDestSrch[index] + "") == "undefined") { document.getElementById("GoogleDestSrch").value = ""; } else { document.getElementById("GoogleDestSrch").value = GoogleDestSrch[index]; } } // -- Destination: 1 * Type of place // input = document.getElementById('GoogleDestSrch'); autocomplete = new google.maps.places.Autocomplete(input); google.maps.event.addListener(autocomplete, 'place_changed', function () { fillInAddress(); }); //]]

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  • C++, using stack.h read a string, then display it in reverse

    - by user1675108
    For my current assignment, I have to use the following header file, #ifndef STACK_H #define STACK_H template <class T, int n> class STACK { private: T a[n]; int counter; public: void MakeStack() { counter = 0; } bool FullStack() { return (counter == n) ? true : false ; } bool EmptyStack() { return (counter == 0) ? true : false ; } void PushStack(T x) { a[counter] = x; counter++; } T PopStack() { counter--; return a[counter]; } }; #endif To write a program that will take a sentence, store it into the "stack", and then display it in reverse, and I have to allow the user to repeat this process as much as they want. The thing is, I am NOT allowed to use arrays (otherwise I wouldn't need help with this), and am finding myself stumped. To give an idea of what I am attempting, here is my code as of posting, which obviously does not work fully but is simply meant to give an idea of the assignment. #include <iostream> #include <cstring> #include <ctime> #include "STACK.h" using namespace std; int main(void) { auto time_t a; auto STACK<char, 256> s; auto string curStr; auto int i; // Displays the current time and date time(&a); cout << "Today is " << ctime(&a) << endl; s.MakeStack(); cin >> curStr; i = 0; do { s.PushStack(curStr[i]); i++; } while (s.FullStack() == false); do { cout << s.PopStack(); } while (s.EmptyStack() == false); return 0; } // end of "main" **UPDATE This is my code currently #include <iostream> #include <string> #include <ctime> #include "STACK.h" using namespace std; time_t a; STACK<char, 256> s; string curStr; int i; int n; // Displays the current time and date time(&a); cout << "Today is " << ctime(&a) << endl; s.MakeStack(); getline(cin, curStr); i = 0; n = curStr.size(); do { s.PushStack(curStr[i++]); i++; }while(i < n); do { cout << s.PopStack(); }while( !(s.EmptyStack()) ); return 0;

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  • iPhone game reading plist file and looping through multi dimensional array.

    - by Fulvio
    I have a question regarding an iPhone game I'm developing. At the moment, below is the code I'm using to currently I loop through my multidimensional array and position bricks accordingly on my scene. Instead of having multiple two dimensional arrays within my code as per the following (gameLevel1). Ideally, I'd like to read from a .plist file within my project and loop through the values in that instead. Please take into account that I'd like to have more than one level within my game (possibly 20) so my .plist file would have to have some sort of separator line item to determine what level I want to render. I was then thinking of having some sort of method that I call and that method would take the level number I'm interested in rendering. e.g. Method? +(void)renderLevel:(NSString levelNumber); e.g. .plist file? #LEVEL_ONE# 0,0,0,0,0,0,0,0,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,1,1,1,1,1,1,1,0 0,0,0,0,0,0,0,0,0 #LEVEL_TWO# 1,0,0,0,0,0,0,0,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 0,1,1,1,1,1,1,1,0 1,1,1,1,1,1,1,1,1 0,1,1,1,1,1,1,1,0 1,1,1,1,1,1,1,1,1 0,1,1,1,1,1,1,1,0 1,1,1,1,1,1,1,1,1 0,1,1,1,1,1,1,1,0 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,1,1,1,1,1,1,1,1 1,0,0,0,0,0,0,0,1 Code that I'm currently using: int gameLevel[17][9] = { { 0,0,0,0,0,0,0,0,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,1,1,1,1,1,1,1,0 }, { 0,0,0,0,0,0,0,0,0 } }; for (int row=0; row < 17; row++) { for (int col=0; col < 9; col++) { thisBrickValue = gameLevel[row][col]; xOffset = 35 * floor(col); yOffset = 22 * floor(row); switch (thisBrickValue) { case 0: brick = [[CCSprite spriteWithFile:@"block0.png"] autorelease]; break; case 1: brick = [[CCSprite spriteWithFile:@"block1.png"] autorelease]; break; } brick.position = ccp(xOffset, yOffset); [self addChild:brick]; } }

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  • Force close message when preferences are called via menu button

    - by Dan T
    I see no problem in the code. Help? preferences.xml <?xml version="1.0" encoding="utf-8"?> <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"> <ListPreference android:title="Gender" android:summary="Are you male or female?" android:key="genderPref" android:defaultValue="male" android:entries="@array/genderArray" android:entryValues="@array/genderValues" /> <ListPreference android:title="Weight" android:summary="How much do you weigh?" android:key="weightPref" android:defaultValue="180" android:entries="@array/weightArray" android:entryValues="@array/weightValues" /> </PreferenceScreen> arrays.xml <?xml version="1.0" encoding="utf-8"?> <resources> <string-array name="genderArray"> <item>Male</item> <item>Female</item> </string-array> <string-array name="genderValues"> <item>male</item> <item>female</item> </string-array> <string-array name="weightArray"> <item>120</item> <item>150</item> <item>180</item> <item>210</item> <item>240</item> <item>270</item> </string-array> <string-array name="weightValues"> <item>120</item> <item>150</item> <item>180</item> <item>210</item> <item>240</item> <item>270</item> </string-array> </resources> Preferences.java: package com.dantoth.drinkingbuddy; import android.os.Bundle; import android.preference.PreferenceActivity; public class Preferences extends PreferenceActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); addPreferencesFromResource(R.xml.preferences); }; } butts.xml (idk why it's butts but I've gotten used to it now. really just sets up the menu button) <?xml version="1.0" encoding="utf-8"?> <menu xmlns:android="http://schemas.android.com/apk/res/android"> <item android:id="@+id/settings" android:title="Settings" android:icon="@drawable/ic_menu_settings" /> <item android:id="@+id/archive" android:title="Archive" android:icon="@drawable/ic_menu_archive" /> <item android:id="@+id/new_session" android:title="New Session" android:icon="@drawable/ic_menu_new" /> <item android:id="@+id/about" android:title="About" android:icon="@drawable/ic_menu_about" /> </menu> within DrinkingBuddy.java: @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.settings: startActivity(new Intent(this, Preferences.class)); return true; case R.id.archive: Toast.makeText(this, "Expect to see your old drinking sessions here.", Toast.LENGTH_LONG).show(); return true; //ETC. } return false; That's it. I can press the menu button on the phone and see the menu items I created, but when I click on the "Settings" (r.id.settings) it FC. Do I have to do anything to the manifest/other thing to get this to work??

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  • this program runs but not correctly:brief decription of what i am trying to do can someone tell me i

    - by user320950
    this is what i have to do: write a program that determines the grade dispersal for 100 students You are to read the exam scores into three arrays, one array for each exam. You must then calculate how many students scored A’s (90 or above), B’s (80 or above), C’s (70 or above), D’s (60 or above), and F’s (less than 60). Do this for each exam and write the distribution to the screen. // basic file operations #include <iostream> #include <fstream> using namespace std; int read_file_in_array(double exam[100][3]); double calculate_total(double exam1[], double exam2[], double exam3[]); // function that calcualates grades to see how many 90,80,70,60 //void display_totals(); double exam[100][3]; int main() { double go,go2,go3; double exam[100][3],exam1[100],exam2[100],exam3[100]; go=read_file_in_array(exam); go2=calculate_total(exam1,exam2,exam3); //go3=display_totals(); cout << go,go2,go3; return 0; } /* int display_totals() { int grade_total; grade_total=calculate_total(exam1,exam2,exam3); return 0; } */ double calculate_total(double exam1[],double exam2[],double exam3[]) { int calc_tot,above90=0, above80=0, above70=0, above60=0,i,j, fail=0; double exam[100][3]; calc_tot=read_file_in_array(exam); for(i=0;i<100;i++) { for (j=0; j<3; j++) { exam1[i]=exam[100][0]; exam2[i]=exam[100][1]; exam3[i]=exam[100][2]; if(exam[i][j] <=90 && exam[i][j] >=100) { above90++; { if(exam[i][j] <=80 && exam[i][j] >=89) { above80++; { if(exam[i][j] <=70 && exam[i][j] >=79) { above70++; { if(exam[i][j] <=60 && exam[i][j] >=69) { above60++; { if(exam[i][j] >=59) { fail++; } } } } } } } } } } } return 0; } int read_file_in_array(double exam[100][3]) { ifstream infile; int exam1[100]; int exam2[100]; int exam3[100]; infile.open("grades.txt");// file containing numbers in 3 columns if(infile.fail()) // checks to see if file opended { cout << "error" << endl; } int num, i=0,j=0; while(!infile.eof()) // reads file to end of line { for(i=0;i<100;i++) // array numbers less than 100 { for(j=0;j<3;j++) // while reading get 1st array or element infile >> exam[i][j]; infile >> exam[i][j]; infile >> exam[i][j]; cout << exam[i][j] << endl; { if (! (infile >> exam[i][j]) ) cout << exam[i][j] << endl; } exam[i][j]=exam1[i]; exam[i][j]=exam2[i]; exam[i][j]=exam3[i]; } infile.close(); } return 0; }

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  • Help with simple linux shell implementation

    - by nunos
    I am implementing a simple version of a linux shell in c. I have succesfully written the parser, but I am having some trouble forking out the child process. However, I think the problem is due to arrays, pointers and such, because just started C with this project and am not still very knowledgable with them. I am getting a segmentation fault and don't know where from. Any help is greatly appreciated. #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <sys/wait.h> #include <sys/types.h> #define MAX_COMMAND_LENGTH 250 #define MAX_ARG_LENGTH 250 typedef enum {false, true} bool; typedef struct { char **arg; char *infile; char *outfile; int background; } Command_Info; int parse_cmd(char *cmd_line, Command_Info *cmd_info) { char *arg; char *args[MAX_ARG_LENGTH]; int i = 0; arg = strtok(cmd_line, " "); while (arg != NULL) { args[i] = arg; arg = strtok(NULL, " "); i++; } int num_elems = i; if (num_elems == 0) return -1; cmd_info->infile = NULL; cmd_info->outfile = NULL; cmd_info->background = 0; int iarg = 0; for (i = 0; i < num_elems-1; i++) { if (!strcmp(args[i], "<")) { if (args[i+1] != NULL) cmd_info->infile = args[++i]; else return -1; } else if (!strcmp(args[i], ">")) { if (args[i+1] != NULL) cmd_info->outfile = args[++i]; else return -1; } else cmd_info->arg[iarg++] = args[i]; } if (!strcmp(args[i], "&")) cmd_info->background = true; else cmd_info->arg[iarg++] = args[i]; cmd_info->arg[iarg] = NULL; return 0; } void print_cmd(Command_Info *cmd_info) { int i; for (i = 0; cmd_info->arg[i] != NULL; i++) printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("infile=\"%s\"\n", cmd_info->infile); printf("outfile=\"%s\"\n", cmd_info->outfile); printf("background=\"%d\"\n", cmd_info->background); } void get_cmd(char* str) { fgets(str, MAX_COMMAND_LENGTH, stdin); str[strlen(str)-1] = '\0'; //apaga o '\n' do fim } pid_t exec_simple(Command_Info *cmd_info) { pid_t pid = fork(); if (pid < 0) { perror("Fork Error"); return -1; } if (pid == 0) { execvp(cmd_info->arg[0], cmd_info->arg); perror(cmd_info->arg[0]); exit(1); } return pid; } int main(int argc, char* argv[]) { while (true) { char cmd_line[MAX_COMMAND_LENGTH]; Command_Info cmd_info; printf(">>> "); get_cmd(cmd_line); if ( (parse_cmd(cmd_line, &cmd_info) == -1) ) return -1; parse_cmd(cmd_line, &cmd_info); if (!strcmp(cmd_info.arg[0], "exit")) exit(0); pid_t pid = exec_simple(&cmd_info); waitpid(pid, NULL, 0); } return 0; } Thanks.

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  • ublas::bounded_vector<> being resized?

    - by n2liquid
    Now, seriously... I'll refrain from using bad words here because we're talking about the Boost fellows. It MUST be my mistake to see things this way, but I can't understand why, so I'll ask it here; maybe someone can enlighten me in this matter. Here it goes: uBLAS has this nice class template called bounded_vector<> that's used to create fixed-size vectors (or so I thought). From the Effective uBLAS wiki (http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?Effective_UBLAS): The default uBLAS vector and matrix types are of variable size. Many linear algebra problems involve vectors with fixed size. 2 and 3 elements are common in geometry! Fixed size storage (akin to C arrays) can be implemented efficiently as it does not involve the overheads (heap management) associated with dynamic storage. uBLAS implements fixed sizes by changing the underling storage of a vector/matrix to a "bounded_array" from the default "unbounded_array". Alright, this bounded_vector<> thing is used to free you from specifying the underlying storage of the vector to a bounded_array<> of the specified size. Here I ask you: doesn't it look like this bounded vector thing has fixed size to you? Well, it doesn't have. At first I felt betrayed by the wiki, but then I reconsidered the meaning of "bounded" and I think I can let it pass. But in case you, like me (I'm still uncertain), is still wondering if this makes sense, what I found out is that the bounded_vector<> actually can be resized, it may only not be greater than the size specified as template parameter. So, first off, do you think they've had a good reason not to make a real fixed<< size vector or matrix type? Do you think it's okay to "sell" this bounded -- as opposed to fixed-size -- vector to the users of my library as a "fixed-size" vector replacement, even named "Vector3" or "Vector2", like the Effective uBLAS wiki did? Do you think I should somehow implement a vector with fixed size for this purpose? If so, how? (Sorry, but I'm really new to uBLAS; just tried it today) I am developing a 3D game. Should uBLAS be used for the calculations involved in this ("hey, geometry!", per Effective uBLAS wiki)? What replacement would you suggest, if not? -- edit And just in case, yes, I've read this warning: It should be noted that this only changes the storage uBLAS uses for the vector3. uBLAS will still use all the same algorithm (which assume a variable size) to manipulate the vector3. In practice this seems to have no negative impact on speed. The above runs just as quickly as a hand crafted vector3 which does not use uBLAS. The only negative impact is that the vector3 always store a "size" member which in this case is redundant [or isn't it? I mean......]. I see it uses the same algorithm, assuming a variable size, but if an operation were to actually change its size, shouldn't it be stopped (assertion)? ublas::bounded_vector<float,3> v3; ublas::bounded_vector<float,2> v2; v3 = v2; std::cout << v3.size() << '\n'; // prints 2 Oh, come on, isn't this just plain betrayal?

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  • this program runs but not correctly numbers arent right, i read numbers from a file and then when i

    - by user320950
    this is what i have to do: write a program that determines the grade dispersal for 100 students You are to read the exam scores into three arrays, one array for each exam. You must then calculate how many students scored A’s (90 or above), B’s (80 or above), C’s (70 or above), D’s (60 or above), and F’s (less than 60). Do this for each exam and write the distribution to the screen. // basic file operations #include <iostream> #include <fstream> using namespace std; int read_file_in_array(double exam[100][3]); double calculate_total(double exam1[], double exam2[], double exam3[]); // function that calcualates grades to see how many 90,80,70,60 //void display_totals(); double exam[100][3]; int main() { double go,go2,go3; double exam[100][3],exam1[100],exam2[100],exam3[100]; go=read_file_in_array(exam); go2=calculate_total(exam1,exam2,exam3); //go3=display_totals(); cout << go,go2,go3; return 0; } /* int display_totals() { int grade_total; grade_total=calculate_total(exam1,exam2,exam3); return 0; } */ double calculate_total(double exam1[],double exam2[],double exam3[]) { int calc_tot,above90=0, above80=0, above70=0, above60=0,i,j, fail=0; double exam[100][3]; calc_tot=read_file_in_array(exam); for(i=0;i<100;i++) { for (j=0; j<3; j++) { exam1[i]=exam[100][0]; exam2[i]=exam[100][1]; exam3[i]=exam[100][2]; if(exam[i][j] <=90 && exam[i][j] >=100) { above90++; { if(exam[i][j] <=80 && exam[i][j] >=89) { above80++; { if(exam[i][j] <=70 && exam[i][j] >=79) { above70++; { if(exam[i][j] <=60 && exam[i][j] >=69) { above60++; { if(exam[i][j] >=59) { fail++; } } } } } } } } } } } return 0; } int read_file_in_array(double exam[100][3]) { ifstream infile; int exam1[100]; int exam2[100]; int exam3[100]; infile.open("grades.txt");// file containing numbers in 3 columns if(infile.fail()) // checks to see if file opended { cout << "error" << endl; } int num, i=0,j=0; while(!infile.eof()) // reads file to end of line { for(i=0;i<100;i++) // array numbers less than 100 { for(j=0;j<3;j++) // while reading get 1st array or element infile >> exam[i][j]; infile >> exam[i][j]; infile >> exam[i][j]; cout << exam[i][j] << endl; { if (! (infile >> exam[i][j]) ) cout << exam[i][j] << endl; } exam[i][j]=exam1[i]; exam[i][j]=exam2[i]; exam[i][j]=exam3[i]; } infile.close(); } return 0; }

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  • android Xml-List view with filter

    - by harisali
    Hi, android is new for me. I am trying to develop a program on 1.5 platform but still in progress, plz guide me. I have some information in following format "item1","description1" "item2","description2" "item3","description3" "item4","description4" . . . . I want to show them on screen, I dont know which is recommended way to do this. After google I found 2 method. but I failed to successfully implement any of one. Method 1 I break both columns data into 2 different arrays, then populate listactivity with array of column 1, enable filter & on clicked event I want to raise alert which should show Text clicked in tilte & desc from 2nd array as msg body based on position. But here is problem if using filter index becomes reinitialize :-(, and there didnot find another way to get text of that row. public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //setContentView(R.layout.main); setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, Names)); getListView().setTextFilterEnabled(true); } public void onListItemClick(ListView parent, View v, int position, long id) { Builder builder = new AlertDialog.Builder(this); builder.setTitle(Names[position]); builder.setMessage(description[position] + " -> " + position ); builder.setPositiveButton("ok", null); builder.show(); } <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello" /> </LinearLayout> its not picking right item from position if filter used :-(, plz guide Can you share source code of this Method B Here I tried to generate list row from XML , but giving error that 1.5 jar file didnot allow modification :-( public View getView(int position, View convertView, ViewGroup parent) { /* ViewInflate inflater=context.getViewInflate(); View row=inflater.inflate(R.layout.row, null, null); */ View row = (View) convertView; if (row==null) { LayoutInflater inflater=context.getLayoutInflater(); // LayoutInflater inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE); row = inflater.inflate(R.layout.row,null); } TextView label=(TextView)row.findViewById(R.id.label); label.setText(items[position]); TextView description=(TextView)row.findViewById(R.id.description); description.setText(items[position]); // ImageView icon=(ImageView)row.findViewById(R.id.icon); // icon.setImageResource(R.drawable.delete); return(row); } Plz suggest what is a right way to acconplish this, so app can show desc of item , has filter too. Plz share If you have any shouce code for this

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  • java - unwanted object overwriting

    - by gosling
    Hello everyone! I'm trying to make a program that solves the logic wheels puzzle. I construct the root node and I try to produce the different child-nodes that are produced by making different moves of the wheels. The problem is that while I try to produce the children, the root node is overwrited,and everything is messed-up and I really don't know why. Here you can find the puzzle logic wheels. I represent the wheels as 3x3 arrays. Here is the code that implements the moves: public Node turn_right(Node aNode, int which_wheel) { Node newNode = new Node(aNode.getYellow_wheel(),aNode.getBlue_wheel(),aNode.getGreen_wheel()); int[][] yellow = new int[3][3]; int[][] blue = new int[3][3]; int[][] green = new int[3][3]; if(which_wheel==0) //turn yellow wheel of this node to right { yellow[1][0] = newNode.getYellow_wheel()[0][0]; yellow[2][0] = newNode.getYellow_wheel()[1][0]; yellow[2][1] = newNode.getYellow_wheel()[2][0]; yellow[2][2] = newNode.getYellow_wheel()[2][1]; yellow[1][2] = newNode.getYellow_wheel()[2][2]; yellow[0][2] = newNode.getYellow_wheel()[1][2]; yellow[0][1] = newNode.getYellow_wheel()[0][2]; yellow[0][0] = newNode.getYellow_wheel()[0][1]; blue = newNode.getBlue_wheel(); blue[1][0] = newNode.getYellow_wheel()[1][2]; blue[2][0] = newNode.getYellow_wheel()[2][2]; green = newNode.getGreen_wheel(); } else if(which_wheel == 1)// turn blue wheel of this node to right { blue[1][0] = newNode.getBlue_wheel()[0][0]; blue[2][0] = newNode.getBlue_wheel()[1][0]; blue[2][1] = newNode.getBlue_wheel()[2][0]; blue[2][2] = newNode.getBlue_wheel()[2][1]; blue[1][2] = newNode.getBlue_wheel()[2][2]; blue[0][2] = newNode.getBlue_wheel()[1][2]; blue[0][1] = newNode.getBlue_wheel()[0][2]; blue[0][0] = newNode.getBlue_wheel()[0][1]; yellow = newNode.getYellow_wheel(); yellow[0][2] = newNode.getBlue_wheel()[0][0]; yellow[1][2] = newNode.getBlue_wheel()[1][0]; green = newNode.getGreen_wheel(); green[1][0] = newNode.getBlue_wheel()[1][2]; green[2][0] = newNode.getBlue_wheel()[2][2]; } else if (which_wheel == 2)//turn green wheel of this node to right { green[0][0] = newNode.getGreen_wheel()[0][1]; green[0][1] = newNode.getGreen_wheel()[0][2]; green[0][2] = newNode.getGreen_wheel()[1][2]; green[1][2] = newNode.getGreen_wheel()[2][2]; green[2][2] = newNode.getGreen_wheel()[2][1]; green[2][1] = newNode.getGreen_wheel()[2][0]; green[2][0] = newNode.getGreen_wheel()[1][0]; green[1][0] = newNode.getGreen_wheel()[0][0]; yellow = newNode.getYellow_wheel(); blue = newNode.getBlue_wheel(); blue[0][2] = newNode.getGreen_wheel()[0][0]; blue[1][2] = newNode.getGreen_wheel()[1][0]; } newNode= new Node(yellow,blue,green); return newNode; } There is another function, like this one that does the oposite:it turns the wheels to left. My problem is that I do not want object's aNode tables to be overwritten. Thank you very much.

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  • Why does this Quicksort work?

    - by IVlad
    I find this Quicksort partitioning approach confusing and wrong, yet it seems to work. I am referring to this pseudocode. Note: they also have a C implementation at the end of the article, but it's very different from their pseudocode, so I don't care about that. I have also written it in C like this, trying to stay true to the pseudocode as much as possible, even if that means doing some weird C stuff: #include <stdio.h> int partition(int a[], int p, int r) { int x = a[p]; int i = p - 1; int j = r + 1; while (1) { do j = j - 1; while (!(a[j] <= x)); do i = i + 1; while (!(a[i] >= x)); if (i < j) { int t = a[i]; a[i] = a[j]; a[j] = t; } else { for (i = 1; i <= a[0]; ++i) printf("%d ", a[i]); printf("- %d\n", j); return j; } } } int main() { int a[100] = //{8, 6,10,13,15,8,3,2,12}; {7, 7, 6, 2, 3, 8, 4, 1}; partition(a, 1, a[0]); return 0; } If you run this, you'll get the following output: 1 6 2 3 4 8 7 - 5 However, this is wrong, isn't it? Clearly a[5] does not have all the values before it lower than it, since a[2] = 6 > a[5] = 4. Not to mention that 7 is supposed to be the pivot (the initial a[p]) and yet its position is both incorrect and lost. The following partition algorithm is taken from wikipedia: int partition2(int a[], int p, int r) { int x = a[r]; int store = p; for (int i = p; i < r; ++i) { if (a[i] <= x) { int t = a[i]; a[i] = a[store]; a[store] = t; ++store; } } int t = a[r]; a[r] = a[store]; a[store] = t; for (int i = 1; i <= a[0]; ++i) printf("%d ", a[i]); printf("- %d\n", store); return store; } And produces this output: 1 6 2 3 8 4 7 - 1 Which is a correct result in my opinion: the pivot (a[r] = a[7]) has reached its final position. However, if I use the initial partitioning function in the following algorithm: void Quicksort(int a[], int p, int r) { if (p < r) { int q = partition(a, p, r); // initial partitioning function Quicksort(a, p, q); Quicksort(a, q + 1, r); // I'm pretty sure q + r was a typo, it doesn't work with q + r. } } ... it seems to be a correct sorting algorithm. I tested it out on a lot of random inputs, including all 0-1 arrays of length 20. I have also tried using this partition function for a selection algorithm, in which it failed to produce correct results. It seems to work and it's even very fast as part of the quicksort algorithm however. So my questions are: Can anyone post an example on which the algorithm DOESN'T work? If not, why does it work, since the partitioning part seems to be wrong? Is this another partitioning approach that I don't know about?

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