Search Results

Search found 11993 results on 480 pages for 'define syntax'.

Page 412/480 | < Previous Page | 408 409 410 411 412 413 414 415 416 417 418 419  | Next Page >

• Solved: Help with this compile error

  - by Scott

  I just picked up an old project and I'm not sure what the following error could mean. g++ -o BufferedReader.o -c -g -Wall -std=c++0x -I/usr/include/xmms2 -Ijsoncpp/include/json/ -fopenmp -I/usr/include/ImageMagick -I/usr/include/xmms2 -I/usr/include/libvisual-0.4 -D_GNU_SOURCE=1 -D_REENTRANT -I/usr/include/SDL -DQT_CORE_LIB -DQT_GUI_LIB -DQT_SCRIPT_LIB -DQT_SHARED -I/usr/include/QtCore -I/usr/include/QtGui -I/usr/include/QtScript BufferedReader.cpp In file included from BufferedReader.cpp:23: /usr/include/string.h:36:42: error: missing binary operator before token "(" In file included from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/cwchar:47, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/bits/postypes.h:42, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/iosfwd:42, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/ios:39, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/istream:40, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/sstream:39, from BufferedReader.cpp:24: At line 24 of BufferedReader.cpp is #include <string.h>. I've tried it with just <string> but get the same thing. Any clue? Here's the snippet of code from string.h /* Tell the caller that we provide correct C++ prototypes. */ #if defined __cplusplus && __GNUC_PREREQ (4, 4) //line 36 # define __CORRECT_ISO_CPP_STRING_H_PROTO #endif Does that mean __GNUC_PREREQ isn't defined? Edit: Changing -Ijsoncpp/include/json/ to Ijsoncpp/include stopped the errors. I noticed I was including <json/json.h>. I'm about to switch to JsonGlib though, which is the reason I pulled the project up again. So it's all good. :)

  Read the article

• jquery append() method on empty XML element

  - by Anthony

  This could just be a syntax error, but I'm trying to create a Document object from scratch, starting with document.implementation.createDocument() and then using jquery's append() method to add the elements. But it's not appending: var myDoc = document.implementation.createDocument("", 'stuff', null); $("stuff",myDoc).attr("test","tested"); $("stuff",myDoc).append("<test>A</test>"); $("<test>B</test>").appendTo("stuff",soapEnv); var s = new XMLSerializer(); alert(s.serializeToString(soapEnv)); This should output: <stuff test="tested"> <test>A</test> <test>B</test> </stuff> But instead it outputs: <stuff test="tested" /> So the selector seems to be working, just not the method. My only guess is the method doesn't account for the fact that elements are empty (<stuff />) until they have children. But that's just a guess.

  Read the article

• What's the best way to get a bunch of rows from MySQL if you have an array of integer primary keys?

  - by Evan P.

  I have a MySQL table with an auto-incremented integer primary key. I want to get a bunch of rows from the table based on an array of integers I have in memory in my program. The array ranges from a handful to about 1000 items. What's the most efficient query syntax to get the rows? I can think of a few: "SELECT * FROM thetable WHERE id IN (1, 2, 3, 4, 5)" (this is what I do now) "SELECT * FROM thetable where id = 1 OR id = 2 OR id = 3" Multiple queries of the form "SELECT * FROM thetable WHERE id = 1". Probably the most friendly to the query cache, but expensive due to having lots of query parsing. A union, like "SELECT * FROM thetable WHERE id = 1 UNION SELECT * FROM thetable WHERE id = 2 ..." I'm not sure if MySQL caches the results of each query; it's also the most verbose format. I think using the NoSQL interface in MySQL 5.6+ would be the most efficient way to do this, but I'm not yet up to MySQL 5.6.

  Read the article

• summing functions handles in matlab

  - by user552231

  Hi I am trying to sum two function handles, but it doesn't work. for example: y1=@(x)(x*x); y2=@(x)(x*x+3*x); y3=y1+y2 The error I receive is "??? Undefined function or method 'plus' for input arguments of type 'function_handle'." This is just a small example, in reality I actually need to iteratively sum about 500 functions that are dependent on each other. EDIT The solution by Clement J. indeed works but I couldn't manage to generalize this into a loop and ran into a problem. I have the function s=@(x,y,z)((1-exp(-x*y)-z)*exp(-x*y)); And I have a vector v that contains 536 data points and another vector w that also contains 536 data points. My goal is to sum up s(v(i),y,w(i)) for i=1...536 Thus getting one function in the variable y which is the sum of 536 functions. The syntax I tried in order to do this is: sum=@(y)(s(v(1),y,z2(1))); for i=2:536 sum=@(y)(sum+s(v(i),y,z2(i))) end

  Read the article

• Queueing method calls - any idea how?

  - by TomTom

  I write a heavily asynchronseous application. I am looking for a way to queue method calls, similar to what BeginInvoke / EndInvoke does.... but on my OWN queue. The reaqson is that I am having my own optimized message queueing system using a threadpool but at the same time making sure every component is single threaded in the requests (i.e. one thread only handles messages for a component). I Have a lot of messages going back and forth. For limited use, I would really love to be able to just queue a message call with parameters, instead of having to define my own parameter, method wrapping / unwrapping just for the sake of doing a lot of admnistrative calls. I also do not always want to bypass the queue, and I definitely do not want the sending service to wait for the other service to respond. Anyone knows of a way to intercept a method call? Some way to utilize TransparentProxy / Virtual Proxy for this? ;) ServicedComponent? I would like this to be as little overhead as possible ;)

  Read the article

• Can I use properties in an ivy.xml file to avoid repeating version numbers of dependencies?

  - by scompt.com

  Here's what part of my ivy.xml looks like right now: <dependency org="org.springframework" name="org.springframework.core" rev="3.0.2.RELEASE" /> <dependency org="org.springframework" name="org.springframework.context" rev="3.0.2.RELEASE" /> <dependency org="org.springframework" name="org.springframework.jdbc" rev="3.0.2.RELEASE" /> <dependency org="org.springframework" name="org.springframework.beans" rev="3.0.2.RELEASE" /> <dependency org="org.springframework" name="org.springframework.jms" rev="3.0.2.RELEASE" /> Here's what I'd like it to look like: <dependency org="org.springframework" name="org.springframework.core" rev="${spring.version}" /> <dependency org="org.springframework" name="org.springframework.context" rev="${spring.version}" /> <dependency org="org.springframework" name="org.springframework.jdbc" rev="${spring.version}" /> <dependency org="org.springframework" name="org.springframework.beans" rev="${spring.version}" /> <dependency org="org.springframework" name="org.springframework.jms" rev="${spring.version}" /> Is this possible? What's the syntax?

  Read the article

• Battery drains even with app off screen, could it be Location Services doing it?

  - by John Jorsett

  I run my app, which uses GPS and Bluetooth, then hit the back button so it goes off screen. I verified via LogCat that the app's onDestroy was called. OnDestroy removes the location listeners and shuts down my app's Bluetooth service. I look at the phone 8 hours later and half the battery charge has been consumed, and my app was responsible according the phone's Battery Use screen. If I use the phone's Settings menu to Force Stop the app, this doesn't occur. So my question is: do I need to do something more than remove the listeners to stop Location Services from consuming power? That's the only thing I can think of that would be draining the battery to that degree when the app is supposedly dormant. Here's my onStart() where I turn on the location-related stuff and Bluetooth: @Override public void onStart() { super.onStart(); if(D_GEN) Log.d(TAG, "MainActivity onStart, adding location listeners"); // If BT is not on, request that it be enabled. // setupBluetooth() will then be called during onActivityResult if (!mBluetoothAdapter.isEnabled()) { Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableIntent, REQUEST_ENABLE_BT); // Otherwise, setup the Bluetooth session } else { if (mBluetoothService == null) setupBluetooth(); } // Define listeners that respond to location updates mLocationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE); mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, GPS_UPDATE_INTERVAL, 0, this); mLocationManager.addGpsStatusListener(this); mLocationManager.addNmeaListener(this); } And here's my onDestroy() where I remove them: public void onDestroy() { super.onDestroy(); if(D_GEN) Log.d(TAG, "MainActivity onDestroy, removing update listeners"); // Remove the location updates if(mLocationManager != null) { mLocationManager.removeUpdates(this); mLocationManager.removeGpsStatusListener(this); mLocationManager.removeNmeaListener(this); } if(D_GEN) Log.d(TAG, "MainActivity onDestroy, finished removing update listeners"); if(D_GEN) Log.d(TAG, "MainActivity onDestroy, stopping Bluetooth"); stopBluetooth(); if(D_GEN) Log.d(TAG, "MainActivity onDestroy finished"); }

  Read the article

• c# Why can't open generic types be passed as parameters?

  - by Rich Oliver

  Why can't open generic types be passed as parameters. I frequently have classes like: public class Example<T> where T: BaseClass { public int a {get; set;} public List<T> mylist {get; set;} } Lets say BaseClass is as follows; public BaseClass { public int num; } I then want a method of say: public int MyArbitarySumMethod(Example example)//This won't compile Example not closed { int sum = 0; foreach(BaseClass i in example.myList)//myList being infered as an IEnumerable sum += i.num; sum = sum * example.a; return sum; } I then have to write an interface just to pass this one class as a parameter as follows: public interface IExample { public int a {get; set;} public IEnumerable<BaseClass> myIEnum {get;} } The generic class then has to be modified to: public class Example<T>: IExample where T: BaseClass { public int a {get; set;} public List<T> mylist {get; set;} public IEnumerable<BaseClass> myIEnum {get {return myList;} } } That's a lot of ceremony for what I would have thought the compiler could infer. Even if something can't be changed I find it psychologically very helpful if I know the reasons / justifications for the absence of Syntax short cuts.

  Read the article

• push(ing)_back objects pointers within a loop

  - by Jose Manuel Albornoz

  Consider the following: I have a class CDevices containing, amongst others, a string member class CDevice { public: CDevice(void); ~CDevice(void); // device name std::string Device_Name; etc... } and somewhere else in my code I define another class that contains a vector of pointers to CDevices class CDevice; class CServers { public: CServers(void); ~CServers(void); // Devices vector vector<CDevice*> Devices; etc... } The problem appears in the following lines in my main.c pDevice = new CDevice; pDevice->Device_Name = "de"; Devices.push_back(pDevice); pDevice->Device_Name = " revolotiunibus"; Devices.push_back(pDevice); pDevice->Device_Name = " orbium"; Devices.push_back(pDevice); pDevice->Device_Name = " coelestium"; Devices.push_back(pDevice); for(int i = 0; i < (int)Devices.size(); ++i) cout << "\nLoad name = " << Devices.at(i)->Device_Name << endl; The output I get is " coelestium" repeated four times: each time I push_back a new element into the vector all of the already existing elements take the value of the one which has just been added. I have also tried using iterators to recover each element in the vector with the same results. Could someone please tell me what's wrong here? Thankx

  Read the article

• filling colors on a map - PHP

  - by jeremy

  I am trying to determine how to fill colors onto a map - such as the "Risk" board game map. I've done this before with HTML tables, by pulling an HTML color code from a SQL table and then just using it to fill the cell the color I want it. But for a non-square map, I'm not sure where to look. I have created a very simple two color map - its white with black borders. My desired result is having the 'regions' on the map shaded with a color, based on data in a sql table (just like the "fill" button in Paint). This looks like what I need: http://php.net/manual/en/function.imagefilltoborder.php and now.. how to define the borders... At the moment I have tried nothing, because the question was: how do I have PHP fill parts of an image? I have tried making an image in Paint, and then scratching my head wondering how to fill parts of it. Having stumbled upon a link, let me focus this a bit more: It appears that with imagefilltoborder that I can put an image on my server, perhaps one that looks like a black and white version of the RISK map - black borders and white everything else. Some questions: Is it correct that the 'border' variable should use the color of my border (whatever value black is) so that the code can "see" where the border is? Is it correct that I'll just need to figure out X,Y coords to begin the fill? Does this work if I have 10 different spots to fill on the map? Can I use varying colors from code or pulled from SQL to assign different colors to those 10 spots, and use 10 different X,Y coords to get them all?

  Read the article

• Weird characters at the beginning of a LPTSTR? C++

  - by extintor

  I am using this code to get the windows version: define BUFSIZE 256 bool config::GetOS(LPTSTR OSv) { OSVERSIONINFOEX osve; BOOL bOsVersionInfoEx; ZeroMemory(&osve, sizeof(OSVERSIONINFOEX)); osve.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX); if( !(bOsVersionInfoEx = GetVersionEx ((OSVERSIONINFO *) &osve)) ) return false; TCHAR buf[BUFSIZE]; StringCchPrintf(buf, BUFSIZE, TEXT("%u.%u.%u.%u"), osve.dwPlatformId, osve.dwMajorVersion, osve.dwMinorVersion, osve.dwBuildNumber); StringCchCat(OSv, BUFSIZE, buf); return true; } And I am testing it with: LPTSTR OSv= new TCHAR[BUFSIZE]; config c; c.GetOS(OSv); MessageBox(OSv, 0, 0); And in the msgbox I get something like this äì5.1.20 (where 5.1.20 is = to OSv) but the first 2 or 3 chars are some weird characters that I don't know when they came from. Even stranger, if I call that second piece again it shows it ok, it only show the weird characters the first time I execute it. Does someone has an idea what's going on here?

  Read the article

• Catch hibernate exceptions with errorpage handler?

  - by membersound

  I'm catching all exceptions within: java.lang.Throwable /page.xhtml java.lang.Error /page.xhtml But what If I get eg a hibernate ex: org.hibernate.exception.ConstraintViolationException Do I have to define error-pages for EVERY maybe occuring exception? Can't I just say "catch every exception"? Update Redirect on a 404 works. But on a throwable does not! <servlet> <servlet-name>Faces Servlet</servlet-name> <servlet-class>javax.faces.webapp.FacesServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>*.jsf</url-pattern> <url-pattern>*.xhtml</url-pattern> </servlet-mapping> <error-page> <exception-type>java.lang.Throwable</exception-type> <location>/error.xhtml</location> </error-page> <error-page> <error-code>404</error-code> <location>/error.xhtml</location> </error-page>

  Read the article

• ASP.NET: Page HTML head rendering

  - by Fabian

  I've been trying to figure out the best way to custom render the <head> element of a pag to get rid of the extra line breaks which is caused by <head runat="server">, so its properly formatted. So far the only thing i've found which works is the following: protected override void Render(HtmlTextWriter writer) { StringWriter stringWriter = new StringWriter(); HtmlTextWriter htmlTextWriter = new HtmlTextWriter(stringWriter); base.Render(htmlTextWriter); htmlTextWriter.Close(); string html = stringWriter.ToString(); string newHTML = html.Replace("\r\n\r\n<!DOCTYPE", "<!DOCTYPE") .Replace("\r\n<html", "<html") .Replace("<title>\r\n\t", "<title>") .Replace("\r\n</title>", "</title>") .Replace("</head>", "\n</head>"); writer.Write(newHTML); } I define my had tag like Now i have 2 questions: How does the above code affect the performance (so is this viable in an production environment)? Is there a better way to do this, for example a method which i can override to just custom render the <head>? Oh yeah ASP.NET MVC is not an option.

  Read the article

• Building Active Record Conditions in an array - private method 'scan' called error

  - by Nick

  Hi, I'm attempting to build a set of conditions dynamically using an array as suggested in the first answer here: http://stackoverflow.com/questions/1658990/one-or-more-params-in-model-find-conditions-with-ruby-on-rails. However I seem to be doing something incorrectly and I'm not sure if what I'm trying is fundamentally unsound or if I'm simply botching my syntax. I'm simplifying down to a single condition here to try to illustrate the issue as I've tried to built a simple Proof of concept along these lines before layering on the 5 different condition styles I'm contending with. This works: excluded.push 12 excluded.push 30 @allsites = Site.all(:conditions => ["id not in (?)", excluded]) This results in a private method 'scan' called error: excluded.push 12 excluded.push 30 conditionsSet << ["id not in (?)", excluded] @allsites = Site.all(:conditions => conditionsSet) Thanks for any advice. I wasn't sure if the proper thing was to put this as a followup item to the related question/answers I noted at the top. Since I've got a problem not an answer. If there is a better way to post this related to the existing post please let me know.

  Read the article

• (Rails) Creating multi-dimensional hashes/arrays from a data set...?

  - by humble_coder

  Hi All, I'm having a bit of an issue wrapping my head around something. I'm currently using a hacked version of Gruff in order to accommodate "Scatter Plots". That said, the data is entered in the form of: g.data("Person1",[12,32,34,55,23],[323,43,23,43,22]) ...where the first item is the ENTITY, the second item is X-COORDs, and the third item is Y-COORDs. I currently have a recordset of items from a table with the columns: POINT, VALUE, TIMESTAMP. Due to the "complex" calculations involved I must grab everything using a single query or risk way too much DB activity. That said, I have a list of items for which I need to dynamically collect all data from the recordset into a hash (or array of arrays) for the creation of the data items. I was thinking something like the following: @h={} e = Events.find_by_sql(my_query) e.each do |event| @h["#{event.Point}"][x] = event.timestamp @h["#{event.Point}"][y] = event.value end Obviously that's not the correct syntax, but that's where my brain is going. Could someone clean this up for me or suggest a more appropriate mechanism by which to accomplish this? Basically the main goal is to keep data for each pointname grouped (but remember the recordset has them all). Much appreciated. EDIT 1 g = Gruff::Scatter.new("600x350") g.title = self.name e = Event.find_by_sql(@sql) h ={} e.each do |event| h[event.Point.to_s] ||= {} h[event.Point.to_s].merge!({event.Timestamp.to_i,event.Value}) end h.each do |p| logger.info p[1].values.inspect g.data(p[0],p[1].keys,p[1].values) end g.write(@chart_file)

  Read the article

• In C/C++ mode in Emacs, change face of code in #if 0...#endif block to comment face

  - by pogopop77

  I'm trying to add functionality found in some other code editors to my Emacs configuration, whereby C/C++ code within #if 0...#endif blocks is automatically set to the comment face/font. Based on my testing, cpp-highlight-mode does something like what I want, but requires user action. It seems like tying into the font-lock functionality is the correct option to make the behavior automatic. I have successfully followed examples in the GNU documentation to change the face of single-line regular expressions. For example: (add-hook 'c-mode-common-hook (lambda () (font-lock-add-keywords nil '(("\\<\\(FIXME\\|TODO\\|HACK\\|fixme\\|todo\\|hack\\)" 1 font-lock-warning-face t))))) works fine to highlight debug related keywords anywhere in a file. However, I am having problems matching #if 0...#endif as a multiline regular expression. I found some useful information in this post (How to compose region like ""), that suggested that Emacs must be told specifically to allow for multiline matches. But this code: (add-hook 'c-mode-common-hook (lambda () '(progn (setq font-lock-multiline t) (font-lock-add-keywords nil '(("#if 0\\(.\\|\n\\)*?#endif" 1 font-lock-comment-face t)))))) still does not work for me. Perhaps my regular expression is wrong (though it appears to work using M-x re-builder), I've messed up my syntax, or I'm following the wrong approach entirely. I'm using Aquamacs 2.1 (which is based on GNU Emacs 23.2.50.1) on OS X 10.6.5, if that makes a difference. Any assistance would be appreciated!

  Read the article

• Perl 500 internal server error. Something wrong with my code.

  - by Nitish

  I get a 500 internal server error when I try to run the code below in a web server which supports perl: #! /usr/bin/perl use LWP; my $ua = LWP::UserAgent->new; $ua->agent("TestApp/0.1 "); $ua->env_proxy(); my $req = HTTP::Request->new(POST => 'http://www.google.com/loc/json'); $req->content_type('application/jsonrequest'); $req->content('{ "cell_towers": [{"location_area_code": "55000", "mobile_network_code": "95", "cell_id": "20491", "mobile_country_code": "404"}], "version": "1.1.0", "request_address": "true"}'); my $res = $ua->request($req); if ($res->is_success) { print $res->content,"\n"; } else { print $res->status_line, "\n"; return undef; } But there is no error when I run the code below: #! /usr/bin/perl use CGI::Carp qw(fatalsToBrowser); print "Content-type: text/html\n\n"; print "<HTML>\n"; print "<HEAD><TITLE>Hello World!</TITLE></HEAD>\n"; print "<BODY>\n"; print "<H2>Hello World!</H2> <br /> \n"; foreach $key (sort keys(%ENV)) { print "$key = $ENV{$key}<p>" ; } print "</BODY>\n"; print "</HTML>\n"; So I think there is some problem with my code. When I run the first perl script in my local machine with the -wc command, it says that the syntax is OK. Help me please.

  Read the article

• typedef a functions prototype

  - by bitmask

  I have a series of functions with the same prototype, say int func1(int a, int b) { // ... } int func2(int a, int b) { // ... } // ... Now, I want to simplify their definition and declaration. Of course I could use a macro like that: #define SP_FUNC(name) int name(int a, int b) But I'd like to keep it in C, so I tried to use the storage specifier typedef for this: typedef int SpFunc(int a, int b); This seems to work fine for the declaration: SpFunc func1; // compiles but not for the definition: SpFunc func1 { // ... } which gives me the following error: error: expected '=', ',', ';', 'asm' or '__attribute__' before '{' token Is there a way to do this correctly or is it impossible? To my understanding of C this should work, but it doesn't. Why? Note, gcc understands what I am trying to do, because, if I write SpFunc func1 = { /* ... */ } it tells me error: function 'func1' is initialized like a variable Which means that gcc understands that SpFunc is a function type.

  Read the article

• Rails load path questions

  - by HelpMe

  Say I have some custom classes that don't belong in models, controllers etc, I should put this in /lib correct? In rails < 3 I would add this directory to my loadpath and in rails 3+ I would add this to my autoload_path. Is this correct? Now say I have some classes that extends already defined classes. Where should I put this so its run on startup. Forexample say I want to add the method 'foo' on String. class String def foo 'foo; end end Where should I put this class so it's defined on startup? Another weird bug I have is when I try to namespace classes in lib. module MyProject class Foo end end Now in a console: ruby-1.9.2-p136 :004 Bags::Foo LoadError: Expected /Users/me/workspace/my_project/lib/foo.rb to define Foo from /Users/rob/.rvm/gems/ruby-1.9.2-p136/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:492:in `load_missing_constant' from /Users/rob/.rvm/gems/ruby-1.9.2-p136/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:183:in `block in const_missing' I keep getting this error. How can I load this file? Thanks in advance for any help!

  Read the article

• Three most critical programming concepts

  - by Todd

  I know this has probably been asked in one form or fashion but I wanted to pose it once again within the context of my situation (and probably others here @ SO). I made a career change to Software Engineering some time ago without having an undergrad or grad degree in CS. I've supplemented my undergrad and grad studies in business with programming courses (VB, Java,C, C#) but never performed academic coursework in the other related disciplines (algorithms, design patterns, discrete math, etc.)...just mostly self-study. I know there are several of you who have either performed interviews and/or made hiring decisions. Given recent trends in demand, what would you say are the three most essential Comp Sci concepts that a developer should have a solid grasp of outside of language syntax? For example, I've seen blog posts of the "Absolute minimum X that every programmer must know" variety...that's what I'm looking for. Again if it's truly a redundancy please feel free to close; my feelings won't be hurt. (Closest ones I could find were http://stackoverflow.com/questions/164048/basic-programming-algorithmic-concepts- which was geared towards a true beginner, and http://stackoverflow.com/questions/648595/essential-areas-of-knowledge-which I didn't feel was concrete enough). Thanks in advance all! T.

  Read the article

• Using static variables for Strings

  - by Vivart

  below content is taken from Best practice: Writing efficient code but i didn't understand why private static String x = "example"; faster than private static final String x ="example"; Can anybody explain this. Using static variables for Strings When you define static fields (also called class fields) of type String, you can increase application speed by using static variables (not final) instead of constants (final). The opposite is true for primitive data types, such as int. For example, you might create a String object as follows: private static final String x = "example"; For this static constant (denoted by the final keyword), each time that you use the constant, a temporary String instance is created. The compiler eliminates "x" and replaces it with the string "example" in the bytecode, so that the BlackBerry® Java® Virtual Machine performs a hash table lookup each time that you reference "x". In contrast, for a static variable (no final keyword), the String is created once. The BlackBerry JVM performs the hash table lookup only when it initializes "x", so access is faster. private static String x = "example"; You can use public constants (that is, final fields), but you must mark variables as private.

  Read the article

• error catching exception while System.out.print

  - by user1702633

  I have 2 classes, one that implements a double lookup( int i); and one where I use that lookup(int i) in solving a question, or in this case printing the lookup values. This case is for an array. So I read the exception documentation or google/textbook and come with the following code: public double lookup(int i) throws Exception { if( i > numItems) throw new Exception("out of bounds"); return items[i]; } and take it over to my class and try to print my set, where set is a name of the object type I define in the class above. public void print() { for (int i = 0; i < set.size() - 1; i++) { System.out.print(set.lookup(i) + ","); } System.out.print(set.lookup(set.size())); } I'm using two print()'s to avoid the last "," in the print, but am getting an unhandled exception Exception (my exception's name was Exception) I think I have to catch my exception in my print() but cannot find the correct formatting online. Do I have to write catch exception Exception? because that gives me a syntax error saying invalid type on catch. Sources like http://docs.oracle.com/javase/tutorial/essential/exceptions/ are of little help to me, I'm can't seem to grasp what the text is telling me. I'm also having trouble finding sources with multiple examples where I can actually understand the coding in the examples. so could anybody give me a source/example for the above catch phrase and perhaps a decent source of examples for new Java programmers? my book is horrendous and I cannot seem to find an understandable example for the above catch phrase online.

  Read the article

• T-SQL: how to sort table rows based on 2 columns

  - by Criss Nautilus

  I'm quite stuck with this problem for sometime now.. How do I sort column A depending on the contents of Column B? I have this sample: ID count columnA ColumnB 12 1 A B 13 2 C D 14 3 B C I want to sort it like this: ID count ColumnA ColumnB 12 1 A B 14 3 B C 13 2 C D so I need to sort the rows if the previous row of ColumnB = the next row of ColumnA I'm thinking a loop? but can't quite imagine how it will work... I was thinking it will go like this (maybe) SELECT a.ID, a.ColumnA, a.ColumnB FROM TableA WITH a (NOLOCK) LEFT JOIN TableA b WITH (NOLOCK) ON a.ID = b.ID and a.counts = b.counts Where a.columnB = b.ColumnA the above code isn't working though and I was thinking more on the lines of... DECLARE @counts int = 1 DECLARE @done int = 0 --WHILE @done = 0 BEGIN SELECT a.ID, a.ColumnA, a.ColumnB FROM TableA WITH a (NOLOCK) LEFT JOIN TableA b WITH (NOLOCK) ON a.ID = b.ID and a.counts = @counts Where a.columnB = b.ColumnA set @count = @count +1 END If this was a C code, would be easier for me but t-sql's syntax is making it a bit harder for a noobie like me.

  Read the article

• How do I overload () operator with two parameters; like (3,5)?

  - by hkBattousai

  I have a mathematical matrix class. It contains a member function which is used to access any element of the class. template >class T> class Matrix { public: // ... void SetElement(T dbElement, uint64_t unRow, uint64_t unCol); // ... }; template <class T> void Matrix<T>::SetElement(T Element, uint64_t unRow, uint64_t unCol) { try { // "TheMatrix" is define as "std::vector<T> TheMatrix" TheMatrix.at(m_unColSize * unRow + unCol) = Element; } catch(std::out_of_range & e) { // Do error handling here } } I'm using this method in my code like this: // create a matrix with 2 rows and 3 columns whose elements are double Matrix<double> matrix(2, 3); // change the value of the element at 1st row and 2nd column to 6.78 matrix.SetElement(6.78, 1, 2); This works well, but I want to use operator overloading to simplify things, like below: Matrix<double> matrix(2, 3); matrix(1, 2) = 6.78; // HOW DO I DO THIS?

  Read the article

• Calling a non-activeX DLL in a VB6 application in Vista/Win7

  - by user1490330

  I have a VB6 app that utilizes a non-activeX DLL (non-registering). It's declared via the classic Public Declare Function "Function Name" Lib "Library.DLL" syntax. On my dev machine (XP) it works fine but when I deploy to Vista or Win7 I'm constantly greeted with a Run Time Error 48 - File Not Found for the DLL in question. I have tried copying that DLL to every directory I can think of including every environment path on the test machine and the app path too. These are all 32-bit test environments so it's not a SysWow64 issue. Possibly throwing a wrench into the mix is the fact that the application in question is an Outlook COM Addin. I managed to install VB6 on Win7 and was able to run a tiny sample app that utilizes this DLL (outside of the Outlook process) so I know it works PROVIDED the DLL is located in App path. If I call App.Path from my DLL when I run it on the test environment it shows, to no surprise, my installation directory however the DLL is there. I tried turning off UAC. I tried making the App.Path directory permissions open to everyone, still no dice.

  Read the article

< Previous Page | 408 409 410 411 412 413 414 415 416 417 418 419  | Next Page >