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  • overloading new/delete problem

    - by hidayat
    This is my scenario, Im trying to overload new and delete globally. I have written my allocator class in a file called allocator.h. And what I am trying to achieve is that if a file is including this header file, my version of new and delete should be used. So in a header file "allocator.h" i have declared the two functions extern void* operator new(std::size_t size); extern void operator delete(void *p, std::size_t size); I the same header file I have a class that does all the allocator stuff, class SmallObjAllocator { ... }; I want to call this class from the new and delete functions and I would like the class to be static, so I have done this: template<unsigned dummy> struct My_SmallObjectAllocatorImpl { static SmallObjAllocator myAlloc; }; template<unsigned dummy> SmallObjAllocator My_SmallObjectAllocatorImpl<dummy>::myAlloc(DEFAULT_CHUNK_SIZE, MAX_OBJ_SIZE); typedef My_SmallObjectAllocatorImpl<0> My_SmallObjectAllocator; and in the cpp file it looks like this: allocator.cc void* operator new(std::size_t size) { std::cout << "using my new" << std::endl; if(size > MAX_OBJ_SIZE) return malloc(size); else return My_SmallObjectAllocator::myAlloc.allocate(size); } void operator delete(void *p, std::size_t size) { if(size > MAX_OBJ_SIZE) free(p); else My_SmallObjectAllocator::myAlloc.deallocate(p, size); } The problem is when I try to call the constructor for the class SmallObjAllocator which is a static object. For some reason the compiler are calling my overloaded function new when initializing it. So it then tries to use My_SmallObjectAllocator::myAlloc.deallocate(p, size); which is not defined so the program crashes. So why are the compiler calling new when I define a static object? and how can I solve it?

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  • C# MultiThread Safe Class Design

    - by Robert
    I'm trying to designing a class and I'm having issues with accessing some of the nested fields and I have some concerns with how multithread safe the whole design is. I would like to know if anyone has a better idea of how this should be designed or if any changes that should be made? using System; using System.Collections; namespace SystemClass { public class Program { static void Main(string[] args) { System system = new System(); //Seems like an awkward way to access all the members dynamic deviceInstance = (((DeviceType)((DeviceGroup)system.deviceGroups[0]).deviceTypes[0]).deviceInstances[0]); Boolean checkLocked = deviceInstance.locked; //Seems like this method for accessing fields might have problems with multithreading foreach (DeviceGroup dg in system.deviceGroups) { foreach (DeviceType dt in dg.deviceTypes) { foreach (dynamic di in dt.deviceInstances) { checkLocked = di.locked; } } } } } public class System { public ArrayList deviceGroups = new ArrayList(); public System() { //API called to get names of all the DeviceGroups deviceGroups.Add(new DeviceGroup("Motherboard")); } } public class DeviceGroup { public ArrayList deviceTypes = new ArrayList(); public DeviceGroup() {} public DeviceGroup(string deviceGroupName) { //API called to get names of all the Devicetypes deviceTypes.Add(new DeviceType("Keyboard")); deviceTypes.Add(new DeviceType("Mouse")); } } public class DeviceType { public ArrayList deviceInstances = new ArrayList(); public bool deviceConnected; public DeviceType() {} public DeviceType(string DeviceType) { //API called to get hardwareIDs of all the device instances deviceInstances.Add(new Mouse("0001")); deviceInstances.Add(new Keyboard("0003")); deviceInstances.Add(new Keyboard("0004")); //Start thread CheckConnection that updates deviceConnected periodically } public void CheckConnection() { //API call to check connection and returns true this.deviceConnected = true; } } public class Keyboard { public string hardwareAddress; public bool keypress; public bool deviceConnected; public Keyboard() {} public Keyboard(string hardwareAddress) { this.hardwareAddress = hardwareAddress; //Start thread to update deviceConnected periodically } public void CheckKeyPress() { //if API returns true this.keypress = true; } } public class Mouse { public string hardwareAddress; public bool click; public Mouse() {} public Mouse(string hardwareAddress) { this.hardwareAddress = hardwareAddress; } public void CheckClick() { //if API returns true this.click = true; } } }

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  • What is the best way to return two values from a method?

    - by Edward Tanguay
    When I have to write methods which return two values, I usually go about it as in the following code which returns a List<string>. Or if I have to return e.g. a id and string, then I return a List<object> and then pick them out with index number and recast the values. This recasting and referencing by index seems inelegant so I want to develop a new habit for methods that return two values. What is the best pattern for this? using System; using System.Collections.Generic; using System.Linq; namespace MultipleReturns { class Program { static void Main(string[] args) { string extension = "txt"; { List<string> entries = GetIdCodeAndFileName("first.txt", extension); Console.WriteLine("{0}, {1}", entries[0], entries[1]); } { List<string> entries = GetIdCodeAndFileName("first", extension); Console.WriteLine("{0}, {1}", entries[0], entries[1]); } Console.ReadLine(); } /// <summary> /// gets "first.txt", "txt" and returns "first", "first.txt" /// gets "first", "txt" and returns "first", "first.txt" /// it is assumed that extensions will always match /// </summary> /// <param name="line"></param> public static List<string> GetIdCodeAndFileName(string line, string extension) { if (line.Contains(".")) { List<string> parts = line.BreakIntoParts("."); List<string> returnItems = new List<string>(); returnItems.Add(parts[0]); returnItems.Add(line); return returnItems; } else { List<string> returnItems = new List<string>(); returnItems.Add(line); returnItems.Add(line + "." + extension); return returnItems; } } } public static class StringHelpers { public static List<string> BreakIntoParts(this string line, string separator) { if (String.IsNullOrEmpty(line)) return null; else { return line.Split(new string[] { separator }, StringSplitOptions.None).Select(p => p.Trim()).ToList(); } } } }

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  • Memory leaks getting sub-images from video (cvGetSubRect)

    - by dnul
    Hi, i'm trying to do video windowing that is: show all frames from a video and also some sub-image from each frame. This sub-image can change size and be taken from a different position of the original frame. So , the code i've written does basically this: cvQueryFrame to get a new image from the video Create a new IplImage (img) with sub-image dimensions ( window.height,window.width) Create a new Cvmat (mat) with sub-image dimensions ( window.height,window.width) CvGetSubRect(originalImage,mat,window) seizes the sub-image transform Mat (cvMat) to img (IplImage) using cvGetImage my problem is that for each frame i create new IplImage and cvMat which take a lot of memory and when i try to free the allocated memory I get a segmentation fault or in the case of the CvMat the allocated space does not get free (valgrind keeps telling me its definetly lost space). the following code does it: int main(void){ CvCapture* capture; CvRect window; CvMat * tmp; //window size window.x=0;window.y=0;window.height=100;window.width=100; IplImage * src=NULL,*bk=NULL,* sub=NULL; capture=cvCreateFileCapture( "somevideo.wmv"); while((src=cvQueryFrame(capture))!=NULL){ cvShowImage("common",src); //get sub-image sub=cvCreateImage(cvSize(window.height,window.width),8,3); tmp =cvCreateMat(window.height, window.width,CV_8UC1); cvGetSubRect(src, tmp , window); sub=cvGetImage(tmp, sub); cvShowImage("Window",sub); //free space if(bk!=NULL) cvReleaseImage(&bk); bk=sub; cvReleaseMat(&tmp); cvWaitKey(20); //window dimensions changes window.width++; window.height++; } } cvReleaseMat(&tmp); does not seem to have any effect on the total amount of lost memory, valgrind reports the same amount of "definetly lost" memory if i comment or uncomment this line. cvReleaseImage(&bk); produces a segmentation fault. notice i'm trying to free the previous sub-frame which i'm backing up in the bk variable. If i comment this line the program runs smoothly but with lots of memory leaks I really need to get rid of memory leaks, can anyone explain me how to correct this or even better how to correctly perform image windowing? Thank you

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  • Copy constructor bug

    - by user168715
    I'm writing a simple nD-vector class, but am encountering a strange bug. I've stripped out the class to the bare minimum that still reproduces the bug: #include <iostream> using namespace std; template<unsigned int size> class nvector { public: nvector() {data_ = new double[size];} ~nvector() {delete[] data_;} template<unsigned int size2> nvector(const nvector<size2> &other) { data_ = new double[size]; int i=0; for(; i<size && i < size2; i++) data_[i] = other[i]; for(; i<size; i++) data_[i] = 0; } double &operator[](int i) {return data_[i];} const double&operator[](int i) const {return data_[i];} private: const nvector<size> &operator=(const nvector<size> &other); //Intentionally unimplemented for now double *data_; }; int main() { nvector<2> vector2d; vector2d[0] = 1; vector2d[1] = 2; nvector<3> vector3d(vector2d); for(int i=0; i<3; i++) cout << vector3d[i] << " "; cout << endl; //Prints 1 2 0 nvector<3> other3d(vector3d); for(int i=0; i<3; i++) cout << other3d[i] << " "; cout << endl; //Prints 1 2 0 } //Segfault??? On the surface this seems to work fine, and both tests print out the correct values. However, at the end of main the program crashes with a segfault, which I've traced to nvector's destructor. At first I thought the (incorrect) default assignment operator was somehow being called, which is why I added the (currently) unimplemented explicit assignment operator to rule this possibility out. So my copy constructor must be buggy, but I'm having one of those days where I'm staring at extremely simple code and just can't see it. Do you guys have any ideas?

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  • Implementing Object Oriented: ansi-C approach

    - by No Money
    Hey there, I am an Intermediate programmer in Java and know some of the basics in C++. I recently started to scam over "C language" [please note that i emphasized on C language and want to stick with C as i found it to be a perfect tool, so no need for suggestions focusing on why should i move back to C++ or Java or any other crappy language (e.g: C#)]. Moving on, I code an Object Oriented approach in C but kindda scramble with the pointers part. Please understand that I am just a noob trying to extend my knowledge beyond what i learned in High School. Here is my code..... #include <stdio.h> typedef struct per{ int privateint; char *privateString; struct per (*New) (); void (*deleteperOBJ) (struct t_person *); void (*setperNumber) ((struct*) t_person,int); void (*setperString) ((struct*) t_person,char *); void (*dumpperState) ((struct*) t_person); }t_person; void setperNumber(t_person *const per,int num){ if(per==NULL) return; per->privateint=num; } void setperString(t_person *const per,char *string){ if(per==NULL) return; per->privateString=string; } void dumpperState(t_person *const per){ if(per==NULL) return; printf("value of private int==%d\n", per->privateint); printf("value of private string==%s\n", per->privateString); } void deleteperOBJ(struct t_person *const per){ free((void*)t_person->per); t_person ->per = NULL; } main(){ t_person *const per = (struct*) malloc(sizeof(t_person)); per = t_person -> struct per -> New(); per -> setperNumber (t_person *per, 123); per -> setperString(t_person *per, "No money"); dumpperState(t_person *per); deleteperOBJ(t_person *per); } Just to warn you, this program has several errors and since I am a beginner I couldn't help except to post this thread as a question. I am looking forward for assistance. Thanks in advance.

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  • Random generates same number in java

    - by user1613360
    This is my java code. import java.io.*; import java.util.*; import java.util.concurrent.TimeUnit; class search { private int numelem; private int[] input=new int[100]; public void setNumofelem() { System.out.println("Enter the total numebr of elements"); Scanner yz=new Scanner(System.in); numelem=yz.nextInt(); } public void randomnumber() throws Exception { int max=500,min=1,n=numelem; Random rand = new Random(); for (int j=0;j < n;j++) { input[j]=rand.nextInt(max)+1; } } public void printinput() { int b=numelem,t=0; while(true) if(b!=0) { System.out.print(" "+input[t]); b--; t++; } else break; } } public class mycode { public static void main(String args[]) throws Exception { search a=new search(); a.setNumofelem(); a.randomnumber(); a.printinput(); } } Now the function randomnumber() just returns the same number.The function executes perfectly if I execute it as a separate java program but fails miserably if I call it using an object.I have also tried the following variations but nothing works everything return the same number. Variation 1: public void randomnumber() throws Exception { int max=500,min=1,n=numelem; Random rand = new Random(); for (int j=0;j < n;j++) { TimeUnit.SECONDS.sleep(1); input[j]=rand.nextInt(max)+1; } } Variation 2: public void randomnumber() throws Exception { int max=500,min=1,n=numelem; Random rand = new Random(); for (int j=0;j < n;j++) { rand.setSeed(System.nanoTime()); input[j]=rand.nextInt(max)+1; } } Variation 3: public void randomnumber() throws Exception { int max=500,min=1,n=numelem; Random rand = new Random(); for (int j=0;j < n;j++) { TimeUnit.SECONDS.sleep(1); rand.setSeed(System.nanoTime()); input[j]=rand.nextInt(max)+1; } } Sample input/Output: Enter the number of elements: 5 23 23 23 23 23 23

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  • Calculating the Angle Between Two vectors Using Dot Product

    - by P. Avery
    I'm trying to calculate the angle between two vectors so that I can rotate a character in the direction of an object in 3D space. I have two vectors( character & object), loc_look, and modelPos respectively. For simplicity's sake I am only trying to rotate along the up axis...yaw. loc_look = D3DXVECTOR3 (0, 0, 1), modelPos = D3DXVECTOR3 (0, 0, 15); I have written this code which seems to be the correct calculations. My problem arises, seemingly, because the rotation I apply to the character's look vector(loc_look) exceeds the value of the object's position (modelPos). Here is my code: BOOL CEntity::TARGET() { if(graphics.m_model->m_enemy) { D3DXVECTOR3 modelPos = graphics.m_model->position; D3DXVec3Normalize(&modelPos, &modelPos); //D3DXVec3Normalize(&loc_look, &loc_look); float dot = D3DXVec3Dot(&loc_look, &modelPos); float yaw = acos(dot); BOOL neg = (loc_look.x > modelPos.x) ? true : false; switch ( neg ) { case false: Yaw(yaw); return true; case true: Yaw(-yaw); return true; } } else return false; } I rotate the character's orientation matrix with the following code: void CEntity::CalculateOrientationMatrix(D3DXMATRIX *orientationMatrix) { D3DXMatrixRotationAxis(&rotY, &loc_up, loc_yaw); D3DXVec3TransformCoord(&loc_look, &loc_look, &rotY); D3DXVec3TransformCoord(&loc_right, &loc_right, &rotY); D3DXMatrixRotationAxis(&rotX, &loc_right, loc_pitch); D3DXVec3TransformCoord(&loc_look, &loc_look, &rotX); D3DXVec3TransformCoord(&loc_up, &loc_up, &rotX); D3DXMatrixRotationAxis(&rotZ, &loc_look, loc_roll); D3DXVec3TransformCoord(&loc_up, &loc_up, &rotZ); D3DXVec3TransformCoord(&loc_right, &loc_right, &rotZ); *orientationMatrix *= rotX * rotY * rotZ; orientationMatrix->_41 = loc_position.x; orientationMatrix->_42 = loc_position.y; orientationMatrix->_43 = loc_position.z; //D3DXVec3Normalize(&loc_look, &loc_look); SetYawPitchRoll(0,0,0); // Reset Yaw, Pitch, & Roll Amounts } Also to note, the modelPos.x increases by 0.1 each iteration so the character will face the object as it moves along the x-axis... Now, when I run program, in the first iteration everything is fine(I haven't rotated the character yet). On the second iteration, the loc_look.x value is greater than the modelPos.x value(I rotated the character too much using the angle specified with the dot product calculations in the TARGET function). Therefore on the second iteration my code will rotate the character left to adjust for the difference in the vectors' x values... How can I tighten up the measurements so that I do not rotate my character's look vector by too great a value?

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  • Nested WHILE loops not acting as expected - Javascript / Google Apps Script

    - by dthor
    I've got a function that isn't acting as intended. Before I continue, I'd like preface this with the fact that I normally program in Mathematica and have been tasked with porting over a Mathematica function (that I wrote) to JavaScript so that it can be used in a Google Docs spreadsheet. I have about 3 hours of JavaScript experience... The entire (small) project is calculating the Gross Die per Wafer, given a wafer and die size (among other inputs). The part that isn't working is where I check to see if any corner of the die is outside of the effective radius, Reff. The function takes a list of X and Y coordinates which, when combined, create the individual XY coord of the center of the die. That is then put into a separate function "maxDistance" that calculates the distance of each of the 4 corners and returns the max. This max value is checked against Reff. If the max is inside the radius, 1 is added to the die count. // Take a list of X and Y values and calculate the Gross Die per Wafer function CoordsToGDW(Reff,xSize,ySize,xCoords,yCoords) { // Initialize Variables var count = 0; // Nested loops create all the x,y coords of the die centers for (var i = 0; i < xCoords.length; i++) { for (var j = 0; j < yCoords.length, j++) { // Add 1 to the die count if the distance is within the effective radius if (maxDistance(xCoords[i],yCoords[j],xSize,ySize) <= Reff) {count = count + 1} } } return count; } Here are some examples of what I'm getting: xArray={-52.25, -42.75, -33.25, -23.75, -14.25, -4.75, 4.75, 14.25, 23.75, 33.25, 42.75, 52.25, 61.75} yArray={-52.5, -45.5, -38.5, -31.5, -24.5, -17.5, -10.5, -3.5, 3.5, 10.5, 17.5, 24.5, 31.5, 38.5, 45.5, 52.5, 59.5} CoordsToGDW(45,9.5,7.0,xArray,yArray) returns: 49 (should be 72) xArray={-36, -28, -20, -12, -4, 4, 12, 20, 28, 36, 44} yArray={-39, -33, -27, -21, -15, -9, -3, 3, 9, 15, 21, 27, 33, 39, 45} CoordsToGDW(32.5,8,6,xArray,yArray) returns: 39 (should be 48) I know that maxDistance() is returning the correct values. So, where's my simple mistake? Also, please forgive me writing some things in Mathematica notation... Edit #1: A little bit of formatting. Edit #2: Per showi, I've changed WHILE loops to FOR loops and replaced <= with <. Still not the right answer. It did clean things up a bit though... Edit #3: What I'm essentially trying to do is take [a,b] and [a,b,c] and return [[a,a],[a,b],[a,c],[b,a],[b,b],[b,c]]

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  • Basic data alignment question

    - by Broken Logic
    I've been playing around to see how my computer works under the hood. What I'm interested in is seeing is what happens on the stack inside a function. To do this I've written the following toy program: #include <stdio.h> void __cdecl Test1(char a, unsigned long long b, char c) { char c1; unsigned long long b1; char a1; c1 = 'b'; b1 = 4; a1 = 'r'; printf("%d %d - %d - %d %d Total: %d\n", (long)&b1 - (long)&a1, (long)&c1 - (long)&b1, (long)&a - (long)&c1, (long)&b - (long)&a, (long)&c - (long)&b, (long)&c - (long)&a1 ); }; struct TestStruct { char a; unsigned long long b; char c; }; void __cdecl Test2(char a, unsigned long long b, char c) { TestStruct locals; locals.a = 'b'; locals.b = 4; locals.c = 'r'; printf("%d %d - %d - %d %d Total: %d\n", (long)&locals.b - (long)&locals.a, (long)&locals.c - (long)&locals.b, (long)&a - (long)&locals.c, (long)&b - (long)&a, (long)&c - (long)&b, (long)&c - (long)&locals.a ); }; int main() { Test1('f', 0, 'o'); Test2('f', 0, 'o'); return 0; } And this spits out the following: 9 19 - 13 - 4 8 Total: 53 8 8 - 24 - 4 8 Total: 52 The function args are well behaved but as the calling convention is specified, I'd expect this. But the local variables are a bit wonky. My question is, why wouldn't these be the same? The second call seems to produce a more compact and better aligned stack. Looking at the ASM is unenlightening (at least to me), as the variable addresses are still aliased there. So I guess this is really a question about the assembler itself allocates the stack to local variables. I realise that any specific answer is likely to be platform specific. I'm more interested in a general explanation unless this quirk really is platform specific. For the record though, I'm compiling with VS2010 on a 64bit Intel machine.

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  • Implications of trying to double free memory space in C

    - by SidNoob
    Here' my piece of code: #include <stdio.h> #include<stdlib.h> struct student{ char *name; }; int main() { struct student s; s.name = malloc(sizeof(char *)); // I hope this is the right way... printf("Name: "); scanf("%[^\n]", s.name); printf("You Entered: \n\n"); printf("%s\n", s.name); free(s.name); // This will cause my code to break } All I know is that dynamic allocation on the 'heap' needs to be freed. My question is, when I run the program, sometimes the code runs successfully. i.e. ./struct Name: Thisis Myname You Entered: Thisis Myname I tried reading this I've concluded that I'm trying to double-free a piece of memory i.e. I'm trying to free a piece of memory that is already free? (hope I'm correct here. If Yes, what could be the Security Implications of a double-free?) While it fails sometimes as its supposed to: ./struct Name: CrazyFishMotorhead Rider You Entered: CrazyFishMotorhead Rider *** glibc detected *** ./struct: free(): invalid next size (fast): 0x08adb008 *** ======= Backtrace: ========= /lib/tls/i686/cmov/libc.so.6(+0x6b161)[0xb7612161] /lib/tls/i686/cmov/libc.so.6(+0x6c9b8)[0xb76139b8] /lib/tls/i686/cmov/libc.so.6(cfree+0x6d)[0xb7616a9d] ./struct[0x8048533] /lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe6)[0xb75bdbd6] ./struct[0x8048441] ======= Memory map: ======== 08048000-08049000 r-xp 00000000 08:01 288098 /root/struct 08049000-0804a000 r--p 00000000 08:01 288098 /root/struct 0804a000-0804b000 rw-p 00001000 08:01 288098 /root/struct 08adb000-08afc000 rw-p 00000000 00:00 0 [heap] b7400000-b7421000 rw-p 00000000 00:00 0 b7421000-b7500000 ---p 00000000 00:00 0 b7575000-b7592000 r-xp 00000000 08:01 788956 /lib/libgcc_s.so.1 b7592000-b7593000 r--p 0001c000 08:01 788956 /lib/libgcc_s.so.1 b7593000-b7594000 rw-p 0001d000 08:01 788956 /lib/libgcc_s.so.1 b75a6000-b75a7000 rw-p 00000000 00:00 0 b75a7000-b76fa000 r-xp 00000000 08:01 920678 /lib/tls/i686/cmov/libc-2.11.1.so b76fa000-b76fc000 r--p 00153000 08:01 920678 /lib/tls/i686/cmov/libc-2.11.1.so b76fc000-b76fd000 rw-p 00155000 08:01 920678 /lib/tls/i686/cmov/libc-2.11.1.so b76fd000-b7700000 rw-p 00000000 00:00 0 b7710000-b7714000 rw-p 00000000 00:00 0 b7714000-b7715000 r-xp 00000000 00:00 0 [vdso] b7715000-b7730000 r-xp 00000000 08:01 788898 /lib/ld-2.11.1.so b7730000-b7731000 r--p 0001a000 08:01 788898 /lib/ld-2.11.1.so b7731000-b7732000 rw-p 0001b000 08:01 788898 /lib/ld-2.11.1.so bffd5000-bfff6000 rw-p 00000000 00:00 0 [stack] Aborted So why is it that my code does work sometimes? i.e. the compiler is not able to detect at times that I'm trying to free an already freed memory. Has it got to do something with my stack/heap size?

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  • Refactoring Singleton Overuse

    - by drharris
    Today I had an epiphany, and it was that I was doing everything wrong. Some history: I inherited a C# application, which was really just a collection of static methods, a completely procedural mess of C# code. I refactored this the best I knew at the time, bringing in lots of post-college OOP knowledge. To make a long story short, many of the entities in code have turned out to be Singletons. Today I realized I needed 3 new classes, which would each follow the same Singleton pattern to match the rest of the software. If I keep tumbling down this slippery slope, eventually every class in my application will be Singleton, which will really be no logically different from the original group of static methods. I need help on rethinking this. I know about Dependency Injection, and that would generally be the strategy to use in breaking the Singleton curse. However, I have a few specific questions related to this refactoring, and all about best practices for doing so. How acceptable is the use of static variables to encapsulate configuration information? I have a brain block on using static, and I think it is due to an early OO class in college where the professor said static was bad. But, should I have to reconfigure the class every time I access it? When accessing hardware, is it ok to leave a static pointer to the addresses and variables needed, or should I continually perform Open() and Close() operations? Right now I have a single method acting as the controller. Specifically, I continually poll several external instruments (via hardware drivers) for data. Should this type of controller be the way to go, or should I spawn separate threads for each instrument at the program's startup? If the latter, how do I make this object oriented? Should I create classes called InstrumentAListener and InstrumentBListener? Or is there some standard way to approach this? Is there a better way to do global configuration? Right now I simply have Configuration.Instance.Foo sprinkled liberally throughout the code. Almost every class uses it, so perhaps keeping it as a Singleton makes sense. Any thoughts? A lot of my classes are things like SerialPortWriter or DataFileWriter, which must sit around waiting for this data to stream in. Since they are active the entire time, how should I arrange these in order to listen for the events generated when data comes in? Any other resources, books, or comments about how to get away from Singletons and other pattern overuse would be helpful.

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  • are C functions declared in <c____> headers guaranteed to be in the global namespace as well as std?

    - by Evan Teran
    So this is something that I've always wondered but was never quite sure about. So it is strictly a matter of curiosity, not a real problem. As far as I understand, what you do something like #include <cstdlib> everything (except macros of course) are declared in the std:: namespace. Every implementation that I've ever seen does this by doing something like the following: #include <stdlib.h> namespace std { using ::abort; // etc.... } Which of course has the effect of things being in both the global namespace and std. Is this behavior guaranteed? Or is it possible that an implementation could put these things in std but not in the global namespace? The only way I can think of to do that would be to have your libstdc++ implement every c function itself placing them in std directly instead of just including the existing libc headers (because there is no mechanism to remove something from a namespace). Which is of course a lot of effort with little to no benefit. The essence of my question is, is the following program strictly conforming and guaranteed to work? #include <cstdio> int main() { ::printf("hello world\n"); } EDIT: The closest I've found is this (17.4.1.2p4): Except as noted in clauses 18 through 27, the contents of each header cname shall be the same as that of the corresponding header name.h, as specified in ISO/IEC 9899:1990 Programming Languages C (Clause 7), or ISO/IEC:1990 Programming Languages—C AMENDMENT 1: C Integrity, (Clause 7), as appropriate, as if by inclusion. In the C + + Standard Library, however, the declarations and definitions (except for names which are defined as macros in C) are within namespace scope (3.3.5) of the namespace std. which to be honest I could interpret either way. "the contents of each header cname shall be the same as that of the corresponding header name.h, as specified in ISO/IEC 9899:1990 Programming Languages C" tells me that they may be required in the global namespace, but "In the C + + Standard Library, however, the declarations and definitions (except for names which are defined as macros in C) are within namespace scope (3.3.5) of the namespace std." says they are in std (but doesn't specify any other scoped they are in).

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  • Basic drawing with Quartz 2D on iPhone

    - by wwrob
    My goal is to make a program that will draw points whenever the screen is touched. This is what I have so far: The header file: #import <UIKit/UIKit.h> @interface ElSimView : UIView { CGPoint firstTouch; CGPoint lastTouch; UIColor *pointColor; CGRect *points; int npoints; } @property CGPoint firstTouch; @property CGPoint lastTouch; @property (nonatomic, retain) UIColor *pointColor; @property CGRect *points; @property int npoints; @end The implementation file: //@synths etc. - (id)initWithFrame:(CGRect)frame { return self; } - (id)initWithCoder:(NSCoder *)coder { if(self = [super initWithCoder:coder]) { self.npoints = 0; } return self; } - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; firstTouch = [touch locationInView:self]; lastTouch = [touch locationInView:self]; } - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; lastTouch = [touch locationInView:self]; points = (CGRect *)malloc(sizeof(CGRect) * ++npoints); points[npoints-1] = CGRectMake(lastTouch.x-15, lastTouch.y-15,30,30); [self setNeedsDisplay]; } - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; lastTouch = [touch locationInView:self]; [self setNeedsDisplay]; } - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetLineWidth(context, 2.0); CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor); CGContextSetFillColorWithColor(context, pointColor.CGColor); for(int i=0; i<npoints; i++) CGContextAddEllipseInRect(context, points[i]); CGContextDrawPath(context, kCGPathFillStroke); } - (void)dealloc { free(points); [super dealloc]; } @end When I load this and click some points, it draws the first points normally, then then next points are drawn along with random ellipses (not even circles). Also I have another question: When is exactly drawRect executed?

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  • C++ segmentation error when first parameter is null in comparison operator overload

    - by user1774515
    I am writing a class called Word, that handles a c string and overloads the <, , <=, = operators. word.h: friend bool operator<(const Word &a, const Word &b); word.cc: bool operator<(const Word &a, const Word &b) { if(a == NULL && b == NULL) return false; if(a == NULL) return true; if(b == NULL) return false; return a.wd < b.wd; //wd is a valid c string } main: char* temp = NULL; //EDIT: i was mistaken, temp is a char pointer Word a("blah"); //a.wd = [b,l,a,h] cout << (temp<a); i get a segmentation error before the first line of the operator< method after the last line in the main. I can correct the problem by writing cout << (a>temp); where the operator> is similarly defined and i get no errors. but my assignment requires (temp < a) to work so this is where i ask for help. EDIT: i made a mistake the first time and i said temp was of type Word, but it is actually of type char*. so i assume that the compiler converts temp to a Word using one of my constructors. i dont know which one it would use and why this would work since the first parameter is not Word. here is the constructor i think is being used to make the Word using temp: Word::Word(char* c, char* delimeters=NULL) { char *temporary = "\0"; if(c == NULL) c = temporary; check(stoppers!=NULL, "(Word(char*,char*))NULL pointer"); //exits the program if the expression is false if(strlen(c) == 0) size = DEFAULT_SIZE; //10 else size = strlen(c) + 1 + DEFAULT_SIZE; wd = new char[size]; check(wd!=NULL, "Word(char*,char*))heap overflow"); delimiters = new char[strlen(stoppers) + 1]; //EDIT: changed to [] check(delimiters!=NULL,"Word(char*,char*))heap overflow"); strcpy(wd,c); strcpy(delimiters,stoppers); count = strlen(wd); } wd is of type char* thanks for looking at this big question and trying to help. let me know if you need more code to look at

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  • C++ Stack Overflow

    - by PhilMAN
    Here is some code: void main() { GameEngine ge("phil", "anotherguy"); string response; do { ge.playGame(); cout << endl << "Do you want to (r)eplay the same battle, (s)tart a new battle, or (q)uit? "; cin >> response; } while(response == "r" || response == "R" || response == "s" || response == "S" ); } GameEngine::GameEngine(string name1, string name2) { p1Name = name1; p2Name = name2; } void GameEngine::playGame() { cout << "PLAY GAME" << endl; Army p1, p2; Battlefield testField; RuleSet rs; int xSize = 13; // Number of rows int ySize = 13; // Number of columns loadData(p1, p2, testField, rs, xSize, ySize); ... } void GameEngine::loadData(Army& p1, Army& p2, Battlefield& testField, RuleSet& rs, int& xSize, int& ySize) { string terrain = BattlefieldUtils::pickTerrain(); string armySplit[14];//id index 1 string ruleSplit[19];//in index 7 string armyP1, armyP2, ruleSet; Skill p1Skills[8]; Skill p2Skills[8]; CreatureStack p1Stacks[20]; CreatureStack p2Stacks[20]; ... } CreatureStack(){quantity = 0; isLive = false; id = -1;}; Army(){}; Battlefield(){}; RuleSet(){}; I have posted every line of code that executes until the program crashes. This code ran fine for a long time, I added some stuff that does not even execute until way after the code I have posted here, and bam stack overflow that occurs at GameEngine::loadData() line: CreatureStack p2Stacks[20]; will not go away. What am I doing wrong here? Is that all the stack can handle? I increased the stack size in Visual Studio and got the error to go away, but that slowed things down considerably, so I would rather just get to the source of the issue and fix that.

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  • Akka framework support for finding duplicate messages

    - by scala_is_awesome
    I'm trying to build a high-performance distributed system with Akka and Scala. If a message requesting an expensive (and side-effect-free) computation arrives, and the exact same computation has already been requested before, I want to avoid computing the result again. If the computation requested previously has already completed and the result is available, I can cache it and re-use it. However, the time window in which duplicate computation can be requested may be arbitrarily small. e.g. I could get a thousand or a million messages requesting the same expensive computation at the same instant for all practical purposes. There is a commercial product called Gigaspaces that supposedly handles this situation. However there seems to be no framework support for dealing with duplicate work requests in Akka at the moment. Given that the Akka framework already has access to all the messages being routed through the framework, it seems that a framework solution could make a lot of sense here. Here is what I am proposing for the Akka framework to do: 1. Create a trait to indicate a type of messages (say, "ExpensiveComputation" or something similar) that are to be subject to the following caching approach. 2. Smartly (hashing etc.) identify identical messages received by (the same or different) actors within a user-configurable time window. Other options: select a maximum buffer size of memory to be used for this purpose, subject to (say LRU) replacement etc. Akka can also choose to cache only the results of messages that were expensive to process; the messages that took very little time to process can be re-processed again if needed; no need to waste precious buffer space caching them and their results. 3. When identical messages (received within that time window, possibly "at the same time instant") are identified, avoid unnecessary duplicate computations. The framework would do this automatically, and essentially, the duplicate messages would never get received by a new actor for processing; they would silently vanish and the result from processing it once (whether that computation was already done in the past, or ongoing right then) would get sent to all appropriate recipients (immediately if already available, and upon completion of the computation if not). Note that messages should be considered identical even if the "reply" fields are different, as long as the semantics/computations they represent are identical in every other respect. Also note that the computation should be purely functional, i.e. free from side-effects, for the caching optimization suggested to work and not change the program semantics at all. If what I am suggesting is not compatible with the Akka way of doing things, and/or if you see some strong reasons why this is a very bad idea, please let me know. Thanks, Is Awesome, Scala

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  • Why does the Ternary\Conditional operator seem significantly faster

    - by Jodrell
    Following on from this question, which I have partially answered. I compile this console app in x64 Release Mode, with optimizations on, and run it from the command line without a debugger attached. using System; using System.Diagnostics; class Program { static void Main() { var stopwatch = new Stopwatch(); var ternary = Looper(10, Ternary); var normal = Looper(10, Normal); if (ternary != normal) { throw new Exception(); } stopwatch.Start(); ternary = Looper(10000000, Ternary); stopWatch.Stop(); Console.WriteLine( "Ternary took {0}ms", stopwatch.ElapsedMilliseconds); stopwatch.Start(); normal = Looper(10000000, Normal); stopWatch.Stop(); Console.WriteLine( "Normal took {0}ms", stopwatch.ElapsedMilliseconds); if (ternary != normal) { throw new Exception(); } Console.ReadKey(); } static int Looper(int iterations, Func<bool, int, int> operation) { var result = 0; for (int i = 0; i < iterations; i++) { var condition = result % 11 == 4; var value = ((i * 11) / 3) % 5; result = operation(condition, value); } return result; } static int Ternary(bool condition, in value) { return value + (condition ? 2 : 1); } static int Normal(int iterations) { if (condition) { return = 2 + value; } return = 1 + value; } } I don't get any exceptions and the output to the console is somthing close to, Ternary took 107ms Normal took 230ms When I break down the CIL for the two logical functions I get this, ... Ternary ... { : ldarg.1 // push second arg : ldarg.0 // push first arg : brtrue.s T // if first arg is true jump to T : ldc.i4.1 // push int32(1) : br.s F // jump to F T: ldc.i4.2 // push int32(2) F: add // add either 1 or 2 to second arg : ret // return result } ... Normal ... { : ldarg.0 // push first arg : brfalse.s F // if first arg is false jump to F : ldc.i4.2 // push int32(2) : ldarg.1 // push second arg : add // add second arg to 2 : ret // return result F: ldc.i4.1 // push int32(1) : ldarg.1 // push second arg : add // add second arg to 1 : ret // return result } Whilst the Ternary CIL is a little shorter, it seems to me that the execution path through the CIL for either function takes 3 loads and 1 or 2 jumps and a return. Why does the Ternary function appear to be twice as fast. I underdtand that, in practice, they are both very quick and indeed, quich enough but, I would like to understand the discrepancy.

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  • Illegal Instruction When Programming C++ on Linux

    - by remagen
    Heyo, My program, which does exactly the same thing every time it runs (moves a point sprite into the distance) will randomly fail with the text on the terminal 'Illegal Instruction'. My googling has found people encountering this when writing assembly which makes sense because assembly throws those kinds of errors. But why would g++ be generating an illegal instruction like this? It's not like I'm compiling for Windows then running on Linux (which even then, as long as both are on x86 shouldn't AFAIK cause an Illegal Instruction). I'll post the main file below. I can't reliably reproduce the error. Although, if I make random changes (add a space here, change a constant there) that force a recompile I can get a binary which will fail with Illegal Instruction every time it is run, until I try setting a break point, which makes the illegal instruction 'dissapear'. :( #include <stdio.h> #include <stdlib.h> #include <GL/gl.h> #include <GL/glu.h> #include <SDL/SDL.h> #include "Screen.h" //Simple SDL wrapper #include "Textures.h" //Simple OpenGL texture wrapper #include "PointSprites.h" //Simple point sprites wrapper double counter = 0; /* Here goes our drawing code */ int drawGLScene() { /* These are to calculate our fps */ static GLint T0 = 0; static GLint Frames = 0; /* Move Left 1.5 Units And Into The Screen 6.0 */ glLoadIdentity(); glTranslatef(0.0f, 0.0f, -6); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); glEnable(GL_POINT_SPRITE_ARB); glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE); glBegin( GL_POINTS ); /* Drawing Using Triangles */ glVertex3d(0.0,0.0, 0); glVertex3d(1.0,0.0, 0); glVertex3d(1.0,1.0, counter); glVertex3d(0.0,1.0, 0); glEnd( ); /* Finished Drawing The Triangle */ /* Move Right 3 Units */ /* Draw it to the screen */ SDL_GL_SwapBuffers( ); /* Gather our frames per second */ Frames++; { GLint t = SDL_GetTicks(); if (t - T0 >= 50) { GLfloat seconds = (t - T0) / 1000.0; GLfloat fps = Frames / seconds; printf("%d frames in %g seconds = %g FPS\n", Frames, seconds, fps); T0 = t; Frames = 0; counter -= .1; } } return 1; } GLuint objectID; int main( int argc, char **argv ) { Screen screen; screen.init(); screen.resize(800,600); LoadBMP("./dist/Debug/GNU-Linux-x86/particle.bmp"); InitPointSprites(); while(true){drawGLScene();} }

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  • synchronized in java - Proper use

    - by ZoharYosef
    I'm building a simple program to use in multi processes (Threads). My question is more to understand - when I have to use a reserved word synchronized? Do I need to use this word in any method that affects the bone variables? I know I can put it on any method that is not static, but I want to understand more. thank you! here is the code: public class Container { // *** data members *** public static final int INIT_SIZE=10; // the first (init) size of the set. public static final int RESCALE=10; // the re-scale factor of this set. private int _sp=0; public Object[] _data; /************ Constructors ************/ public Container(){ _sp=0; _data = new Object[INIT_SIZE]; } public Container(Container other) { // copy constructor this(); for(int i=0;i<other.size();i++) this.add(other.at(i)); } /** return true is this collection is empty, else return false. */ public synchronized boolean isEmpty() {return _sp==0;} /** add an Object to this set */ public synchronized void add (Object p){ if (_sp==_data.length) rescale(RESCALE); _data[_sp] = p; // shellow copy semantic. _sp++; } /** returns the actual amount of Objects contained in this collection */ public synchronized int size() {return _sp;} /** returns true if this container contains an element which is equals to ob */ public synchronized boolean isMember(Object ob) { return get(ob)!=-1; } /** return the index of the first object which equals ob, if none returns -1 */ public synchronized int get(Object ob) { int ans=-1; for(int i=0;i<size();i=i+1) if(at(i).equals(ob)) return i; return ans; } /** returns the element located at the ind place in this container (null if out of range) */ public synchronized Object at(int p){ if (p>=0 && p<size()) return _data[p]; else return null; }

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  • What the best approach to iterate and "store" files over a directory in C (Linux) ?

    - by Andrei Ciobanu
    I have written a function that checks if to files are duplicates or not. This function signature is: int check_dup_memmap(char *f1_name, char *f2_name) It returns: (-1) - If something went wrong; (0) - If the two files are similar; (+1) - If the two files are different; The next step is to write a function that iterates through all the files in a certain directory,apply the previous function, and gives a report on every existing duplicates. Initially I've thought to write a function that generates a file with all the filenames in a certain directory and then, read that file again and gain and compare every two files. Here is that version of the function, that gets all the filenames in a certain directory. void *build_dir_tree(char *dirname, FILE *f) { DIR *cdir = NULL; struct dirent *ent = NULL; struct stat buf; if(f == NULL){ fprintf(stderr, "NULL file submitted. [build_dir_tree].\n"); exit(-1); } if(dirname == NULL){ fprintf(stderr, "NULL dirname submitted. [build_dir_tree].\n"); exit(-1); } if((cdir = opendir(dirname)) == NULL){ char emsg[MFILE_LEN]; sprintf(emsg, "Cannot open dir: %s [build_dir_tree]\t",dirname); perror(emsg); } chdir(dirname); while ((ent = readdir(cdir)) != NULL) { lstat(ent->d_name, &buf); if (S_ISDIR(buf.st_mode)) { if (strcmp(".", ent->d_name) == 0 || strcmp("..", ent->d_name) == 0) { continue; } build_dir_tree(ent->d_name, f); } else{ fprintf(f, "/%s/%s\n",util_get_cwd(),ent->d_name); } } chdir(".."); closedir(cdir); } Still I consider this approach a little inefficient, as I have to parse the file again and again. In your opinion what are other approaches should I follow: Write a datastructure and hold the files instead of writing them in the file ? I think for a directory with a lot of files, the memory will become very fragmented. Hold all the filenames in auto-expanding array, so that I can easy access every file by their index, because they will in a contiguous memory location. Map this file in memory using mmap() ? But mmap may fail, as the file gets to big. Any opinions on this. I want to choose the most efficient path, and access as few resources as possible. This is the requirement of the program... EDIT: Is there a way to get the numbers of files in a certain directory, without iterating through it ?

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  • Weird Datagrid / paint behaviour

    - by Shane.C
    The scenario: A method sends out a broadcast packet, and returned packets that are validated are deemed okay to be added as a row in my datagrid (The returned packets are from devices i want to add into my program). So for each packet returned, containing information about a device, i create a new row. This is done by first sending packets out, creating rows and adding them to a list of rows that are to be added, and then after 5 seconds (In which case all packets would have returned by then) i add the rows. Here's a few snippets of code. Here for each returned packet, i create a row and add it to a list; DataRow row = DGSource.NewRow(); row["Name"] = deviceName; row["Model"] = deviceModel; row["Location"] = deviceLocation; row["IP"] = finishedIP; row["MAC"] = finishedMac; row["Subnet"] = finishedSubnet; row["Gateway"] = finishedGateway; rowsToAdd.Add(row); Then when the timer elapses; void timerToAddRows_Elapsed(object sender, System.Timers.ElapsedEventArgs e) { timerToAddRows.Enabled = false; try { int count = 0; foreach (DataRow rowToAdd in rowsToAdd) { DGSource.Rows.Add(rowToAdd); count++; } rowsToAdd.Clear(); DGAutoDevices.InvokeEx(f => DGAutoDevices.Refresh()); lblNumberFound.InvokeEx(f => lblNumberFound.Text = count + " new devices found."); } catch { } } So at this point, each row has been added, and i call the re paint, by doing refresh. (Note: i've also tried refreshing the form itself, no avail). However, when the datagrid shows the rows, the scroll bar / datagrid seems to have weird behavour..for example i can't highlight anything with clicks (It's set to full row selection), and the scroll bar looks like so; Calling refresh doesn't work, although if i resize the window even 1 pixel, or minimize and maximise, the problem is solved. Other things to note : The method that get's the packets and adds the rows to the list, and then from the list to the datagrid runs in it's own thread. Any ideas as to something i might be missing here?

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  • Zend Framework-where should this root.php file go for MVC?

    - by Joel
    Hi guys, I'm converting over a web-app to use the MVC structure of Zend Framework. I have a root.php include file that contains most of the database info, and some static variables that are used in the program. I'm not sure if some of this should be in the application.ini of in a model that is called by the init() function in a controller, or in the bootstrap or what? Any help would be much appreciated! root.php (include file at the top of every php page): <?php /*** //Configuration file */ ## Site Configuration starts ## define("SITE_ROOT" , dirname(__FILE__)); define("SITE_URL" , "http://localhost/monkeycalendarapp/monkeycalendarapp/public"); define('DB_HOST', "localhost"); define('DB_USER', "root"); define('DB_PASS', "xxx"); define('DB_NAME', "xxxxx"); define("PROJECT_NAME" , "Monkey Mind Manager (beta 2.2)"); //site title define("CALENDAR_WIDTH" , "300"); //left mini calendar width define("CALENDAR_HEIGHT" , "150"); //left mini calendar height $page_title = 'Event List'; $stylesheet_name = 'style.css'; //default stylesheet define("SITE_URL_AJAX" , SITE_URL . "/ajax-tooltip"); define("JQUERY" , SITE_URL . "/jquery-ui-1.7.2"); $a_times = array("12:00","12:30","01:00","01:30","02:00","02:30","03:00","03:30","04:00","04:30","05:00","05:30","06:00","06:30","07:00","07:30","08:00","08:30","09:00","09:30","10:00","10:30","11:00","11:30"); //PTLType Promotional timeline type $a_ptlType= array(1=>"Gigs","To-Do","Completed"); $a_days = array("Su","Mo","Tu","We","Th","Fr","Sa"); $a_timesMerd = array("12:00am","12:30am","01:00am","01:30am","02:00am","02:30am","03:00am","03:30am","04:00am","04:30am","05:00am","05:30am","06:00am","06:30am","07:00am","07:30am","08:00am","08:30am","09:00am","09:30am","10:00am","10:30am","11:00am","11:30am","12:00pm","12:30pm","01:00pm","01:30pm","02:00pm","02:30pm","03:00pm","03:30pm","04:00pm","04:30pm","05:00pm","05:30pm","06:00pm","06:30pm","07:00pm","07:30pm","08:00pm","08:30pm","09:00pm","09:30pm","10:00pm","10:30pm","11:00pm","11:30pm"); //Setting stylesheet for this user. $AMPM=array("am"=>"am","pm"=>"pm"); include(SITE_ROOT . "/includes/functions/general.php"); include(SITE_ROOT . "/includes/db.php"); session_start(); if(isset($_SESSION['userData']['UserID'])) { $s_userID = $_SESSION['userData']['UserID']; } $stylesheet_name = stylesheet(); ini_set('date.timezone', 'GMT'); date_default_timezone_set('GMT'); if($s_userID) { ini_set('date.timezone', $_SESSION['userData']['timezone']); date_default_timezone_set($_SESSION['userData']['timezone']); } ?>

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  • c# Lambda Expression built with LinqKit does not compile

    - by Frank Michael Kraft
    This lambda does not compile, but I do not understand why. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Linq.Expressions; using LinqKit; namespace ConsoleApplication2 { class Program { static void Main(string[] args) { var barModel = new BarModel(); string id = "some"; Console.WriteLine(barModel.subFor(id).ToString()); // output: m => (True AndAlso (m.key == value(ConsoleApplication2.Bar`1+<>c__DisplayClass0[ConsoleApplication2.Model]).id)) Console.ReadKey(); var subworkitems = barModel.list.Where(barModel.subFor(id).Compile()); // Exception {"variable 'm' of type 'ConsoleApplication2.Model' referenced from scope '', but it is not defined"} Console.WriteLine(subworkitems.ToString()); Console.ReadKey(); } } class Bar<TModel> { public Bar(Expression<Func<TModel, string>> foreignKeyExpression) { _foreignKeyExpression = foreignKeyExpression; } private Expression<Func<TModel, string>> _foreignKeyExpression { get; set; } public Expression<Func<TModel, bool>> subFor(string id) { var ex = forTargetId(id); return ex; } public Expression<Func<TModel, bool>> forTargetId(String id) { var fc = _foreignKeyExpression; Expression<Func<TModel, bool>> predicate = m => true; var result = predicate.And(m => fc.Invoke(m) == id).Expand(); return result; } } class Model { public string key; public string value; } class BarModel : Bar<Model> { public List<Model> list; public BarModel() : base(m => m.key) { list = new List<Model>(); } } }

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  • Split string in C every white space

    - by redsolja
    I want to write a program in C that displays each word of a whole sentence (taken as input) at a seperate line. This is what i have done so far: void manipulate(char *buffer); int get_words(char *buffer); int main(){ char buff[100]; printf("sizeof %d\nstrlen %d\n", sizeof(buff), strlen(buff)); // Debugging reasons bzero(buff, sizeof(buff)); printf("Give me the text:\n"); fgets(buff, sizeof(buff), stdin); manipulate(buff); return 0; } int get_words(char *buffer){ // Function that gets the word count, by counting the spaces. int count; int wordcount = 0; char ch; for (count = 0; count < strlen(buffer); count ++){ ch = buffer[count]; if((isblank(ch)) || (buffer[count] == '\0')){ // if the character is blank, or null byte add 1 to the wordcounter wordcount += 1; } } printf("%d\n\n", wordcount); return wordcount; } void manipulate(char *buffer){ int words = get_words(buffer); char *newbuff[words]; char *ptr; int count = 0; int count2 = 0; char ch = '\n'; ptr = buffer; bzero(newbuff, sizeof(newbuff)); for (count = 0; count < 100; count ++){ ch = buffer[count]; if (isblank(ch) || buffer[count] == '\0'){ buffer[count] = '\0'; if((newbuff[count2] = (char *)malloc(strlen(buffer))) == NULL) { printf("MALLOC ERROR!\n"); exit(-1); } strcpy(newbuff[count2], ptr); printf("\n%s\n",newbuff[count2]); ptr = &buffer[count + 1]; count2 ++; } } } Although the output is what i want, i have really many black spaces after the final word displayed, and the malloc() returns NULL so the MALLOC ERROR! is displayed in the end. I can understand that there is a mistake at my malloc() implementation but i do not know what it is. Is there another more elegant - generally better way to do it? Thanks in advance.

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