I have QT 5.1.1 installed on my machine, but I'm having some troubles using it. I'm trying to run the following simple program that requires QT:
//Playing Video
#include "cv.h"
#include "opencv2\objdetect\objdetect.hpp"
#include "opencv2\core\core.hpp"
#include "opencv2\highgui\highgui.hpp"
#include "opencv2\features2d\features2d.hpp"
#include "opencv2\calib3d\calib3d.hpp"
#include "opencv2\nonfree\nonfree.hpp"
#include "highgui.h"
#include <openbr\openbr_plugin.h>
using namespace cv;
static void printTemplate(const br::Template &t)
{
const QPoint firstEye = t.file.get<QPoint>("Affine_0");
const QPoint secondEye = t.file.get<QPoint>("Affine_1");
printf("%s eyes: (%d, %d) (%d, %d)\n", qPrintable(t.file.fileName()), firstEye.x(), firstEye.y(), secondEye.x(), secondEye.y());
}
int main(int argc, char *argv[])
{
br::Context::initialize(argc, argv);
// Retrieve classes for enrolling and comparing templates using the FaceRecognition algorithm
QSharedPointer<br::Transform> transform = br::Transform::fromAlgorithm("FaceRecognition");
QSharedPointer<br::Distance> distance = br::Distance::fromAlgorithm("FaceRecognition");
// Initialize templates
br::Template queryA("../data/MEDS/img/S354-01-t10_01.jpg");
br::Template queryB("../data/MEDS/img/S382-08-t10_01.jpg");
br::Template target("../data/MEDS/img/S354-02-t10_01.jpg");
// Enroll templates
queryA >> *transform;
queryB >> *transform;
target >> *transform;
printTemplate(queryA);
printTemplate(queryB);
printTemplate(target);
// Compare templates
float comparisonA = distance->compare(target, queryA);
float comparisonB = distance->compare(target, queryB);
// Scores range from 0 to 1 and represent match probability
printf("Genuine match score: %.3f\n", comparisonA);
printf("Impostor match score: %.3f\n", comparisonB);
br::Context::finalize();
return 0;
}
It also requires OpenCV 2.4.6.1 and OpenBR, but that's not the problem.
All the definitions (variables and functions) in the above code that are related to QT are undefined. I've tried to find the relevant h files in QT folder and to include them, but that did not succeed since I couldn't fine qtcore.h (but a different file named qtcore with lot's of includes that I don't now how to use). I've tried to add QT "include" directory under "additional include directories" in the project properties but that didn't work either. I've also tried to add QT "lib" folder under "additional library directories" but that also did not work.
Basically, I tried everything I could think of. Can someone please explain how to I use those QT definitions? I'm really stuck and I could use any help given.
Thanks,
Gil.
(Optional) Update to Qt 5.2.
Start Qt Creator.
Create a new Qt Widgets Application project. You can give the class/files random names, it doesn't matter. Uncheck the "generate form" option, as you don't need any forms.
Remove all the files other than main.cpp from the project. You do this by right-clicking on them in the project tree on the left and choosing Remove File.
Copy-paste your code into main cpp. Make sure you completely replace main.cpp's contents, the default contents shouldn't be there anymore.
Add the opencv library to the project. Right-click on the project's root, select "Add Library", and go from there.
Re-run qmake by right-clicking on the project root and selecting "Run qmake".
Build and run the project by pressing Ctrl-R (Cmd-R on mac).
Qt uses a (non-standard) custom toolchain that has to run before the Qt-dependent code can be compiled. I've never tried using Qt outside of QtCreator, but if you really need Qt I'd suggest you use the QtCreator IDE; if you're not using it already of course. It's a very decent IDE, even for non-Qt projects.
Also, if you haven't done so already, make sure the Qt SDK is installed; the headers alone are not enough. QtCreator by itself is also not enough, you'll need the SDK. If you don't feel like doing so, my suggestion would be to look at Poco. It's not a 1:1 replacement for Qt, but a very mature framework nevertheless.
Related
Until recently I've used C++Builder 10.2 for a project, and I had begun to use DUnitX to add some unit tests for the project.
Now I have upgraded to C++Builder 11.2, and found that DunitX is no longer supported for C++Builder when using this version. Instead, Embarcadero recommends to use DUnit or Googletest.
On further research, it seems that Googletest cannot be used with the classic compiler (but I'm not actually interested in using the pre-C++11 classic compiler), but also that DUnit cannot be used when targeting the Firemonkey framework, and that DUnit (1) is unmaintained and (2) does not work well with the Clang-based compiler.
I'm interested in using googletest because I have already used both, googletest and googlemock, on less niche platforms than C++Builder such as Linux/GCC, Apple/Clang and Windows/MinGW-w64. I am aware that the googletest project itself refuses to accept build files or patches for C++Builder because they do not want to spend effort to support niche compilers (see e.g. here, here, and here).
I'm happy to learn that some patched version of googletest is currently available for C++Builder through the GetIt package manager, even though it is not clear who has actually made that patch, and although I realize that Embarcadero may remove googletest from the GetIt package manager an any moment.
I've found two blog posts explaining how to install googletest in C++Builder and how to use it, however, I cannot successfully follow the second blog post when it comes to point 6, which reads
In your project group create a new windows64 bit VCL console application. Set this to use the debug settings (this allows you to debug code that doesn’t pass a unit test).As well as the files you want to test and the files containing the testing code you need to add to the project the library file …GT2021.09\cbuilder\lib\Win64\Debug\gtest.a.
I'm not sure how I am supposed to "add to the project the library file". I've tried to
copy the gtest.a and gmock.a files into the project directory and then
right-click on the project name in the "Projects" view of the IDE and select "Add...", then change file type to "static libraries", then select gtest.a and repeat with gmock.a.
Here I've gone ahead and have already added gmock.a because I have experience with googlemock and envision that its additional matchers and mock class generators will help me writing tests.
When I compile a simple test project that does not actually perform any tests, everything compiles and links fine, but when I execute the resulting command line program, then it fails with exit code (errorlevel) -1073741819 and produces no output. This does not happen if I comment all usages of googletest out.
The simple test project which fails during execution consists only of
#include <gtest/gtest.h>
#include <vcl.h>
#include <tchar.h>
int _tmain(int argc, _TCHAR* argv[])
{
testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
which should cause googletest to print that 0 tests were executed, but instead it crashes as described. When replacing the two lines in main with a simple printf, which does not use googletest, but leaving all includes unaltered and without altering the project with regard to libraries, it works fine (the new printf prints something) but of course cannot perform any tests.
How to fix this?
One more observation: When adding the static libraries to the project as described above, I get a notification message box from the IDE, saying "One or multiple lines were too long and have been truncated". I have no idea how this message could make sense with regard to adding a static library to the project. It seems however, that this is not an error, and the linker actually uses the static libraries when linking.
The main problem here was the inclusion of the gmock.a library as it was compiled by the GetIt googletest package. This gmock project and basically all other gmock projects in the GetIt package are broken and need to be repaired before using them. I may post more details about this in a future topic. The gmock.cbproj project as distributed by GetIt, e.g., includes the unrelated source file googletest\samples\sample8_unittest.cc, among other errors.
A simple method to use googletest with C++Builder 11.2, which is based on the blog posts by Cigol, but which does not require to copy include files and library files:
When installing googletest with the getit package manager, the IDE automatically opens a group project Googletest.groupproj and compiles two of the contained projects (gtest and gtest_main) for the Windows 64 bit platform in "Release" mode. Furthermore, all other project files in the Googletest project group are modified probably because they have been updated from an earlier C++Builder version and want to be saved when closing the IDE.
There is no need to compile googletest in "Debug" mode, one would need that only for debugging the unit testing framework itself.
Next, create a new VCL Windows 64 bit console application to start using googletest:
File -> New -> "Console Application - C++Builder"
Source Type: C++, Target Framework: Visual Component Library, [OK]
Add Target Platform Windows 64-Bit in the "Projects" view (right-click on Target Platforms).
Delete Target Platform Windows 32-Bit.
Save all in a dedicated directory:
File -> Save All
Create a new folder, e.g. MyUnitTests.
Place project file as e.g. MyUnitTests.cbproj into that folder.
Rename File1.cpp to MyTestsMain.cpp and store in that folder
This creates a C++ source file MyTestsMain.cpp with some includes and an empty main function:
#include <vcl.h>
#include <tchar.h>
int _tmain(int argc, _TCHAR* argv[])
{
}
For convenience, googletest provides a library gtest_main.a which only contains a main function that one can use to execute all unit tests compiled into an executable. By linking against the gtest_main.a library, users can avoid writing their own main function and concentrate on only writing test code. But since the C++Builder wizard has already created a main function, one can as well fill the generated main function with the necessary boilerplate code (only two lines are required, compare against the googletest main function in C:\Users\yourLogin\Documents\Embarcadero\Studio\22.0\CatalogRepository\GoogleTest-2021.09\googletest\src\gtest_main.cc) and add the gtest.h include directive:
#include <gtest/gtest.h>
#include <vcl.h>
#include <tchar.h>
int _tmain(int argc, _TCHAR* argv[])
{
testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
Trying to build this project fails because the gtest/gtest.h include file is not found. This can be fixed in Project -> "Options..." -> Building -> C++ Shared Options -> "Include path": After selecting "All configurations - All platforms" in the drop-down list "Target", add the following entry to "Include path":
$(BDSCatalogRepository)\GoogleTest-2021.09\googletest\include
Using the variable $(BDSCatalogRepository) avoids machine- and developer-specific absolute PATHs. Save the changed project settings with File -> "Save all". Trying again to build this project now fails because of different errors, which is progress! The errors now are "Unresolved external"s, which means we have to tell the project to link against gtest.a and where to find it. Linking against gtest.a can be done by adding a pragma to the top of the file containing the main function:
#pragma comment(lib,"gtest")
#include <gtest/gtest.h>
#include <vcl.h>
#include <tchar.h>
int _tmain(int argc, _TCHAR* argv[])
{
testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
Where to find the library can be configured in Project -> "Options..." -> Building -> C++ Shared Options -> "Library path": Again first select "All configurations - All Platforms", then add the following entry to "Library path":
$(BDSCatalogRepository)\GoogleTest-2021.09\cbuilder\lib\$(Platform)\Release
After File -> "Save All", a new, clean build generates different "Unresolved external"s, progress! This time, symbols from the standard C++ library are missing, which can be fixed via Project -> "Options..." -> Building -> C++ Linker, again for Target "All configurations - All platforms", check the checkbox "Link with Dynamic RTL, Windows...". After another File -> "Save All", a clean build succeeds and executing the generated Win64\Debug\MyUnitTests.exe generates this output:
[==========] Running 0 tests from 0 test suites.
[==========] 0 tests from 0 test suites ran. (0 ms total)
[ PASSED ] 0 tests.
One can now add tests to the test project. Tests can be added to the source file which contains the main function or to different, topic-specific source files. I'll add two tests in new files for demonstration:
In the "Projects" view, right click on the current project, which is confusingly named "MyUnitTest.exe" in the project view with an ".exe" extension instead of a project file extension, then select "Add new..." -> Unit in the popup menu. "Unit" here is C++Builder's language for a pair of one source and one header file, and is not necessarily related to unit testing.
The new files are initially named "Unit1.cpp" and "Unit1.h" but can be renamed when doing File -> "Save All". I name this first test file to "SelfContainedTest.cpp" because its test will be self-contained. Add the following code to the .cpp file after the IDE-Generated boilerplate:
#include <gtest/gtest.h>
TEST(SelfContained, Addition) {
EXPECT_EQ(3, 1+2);
EXPECT_GT(3, 2+2);
}
Rebuilding succeeds, execution reveals that the second EXPECT fails as it should, the number 3 is in fact not greater than the sum 2+2. Fix if you like.
In a second test, I want to test non-GUI methods of an existing VCL form. In a real-world scenario, the GUI project and my test project would be part of the same project group and live in the same directory or below the same parent directory, and I would add the VCL form's .cpp file also to the test project with (Project View) -> right click -> "Add..." -> C++Builder unit (*.cpp). My form TAdderForm that I'm using here is a simple form with two VCL TEdit fields for entering numbers and a VCL TLabel to display the sum of the two numbers. The sum is computed in a method
int TAdderForm::add(int num1, int num2)
{
return num1 + num2;
}
which I want to test here. To write the test, I add a new "Unit" to the test project as before, naming the source file "VCLTest.cpp" this time. After the IDE-generated boilerplate, I add this code to the .cpp file:
#include "adderFormx.h"
#include <gtest/gtest.h>
TEST(VCL, Addition) {
// Have to instantiate VCL form before calling its method.
Application->CreateForm(__classid(TAdderForm), &AdderForm);
EXPECT_EQ(3, AdderForm->add(1,2));
EXPECT_GT(3, AdderForm->add(2,2));
delete AdderForm; // Delete no longer used form.
AdderForm = nullptr; // clear pointer, another test may allocate new instance
}
This is basically the same test as before. The second expectation will fail again and needs to be fixed because 3>4 is a wrong expectation. The test uses the global instance pointer "AdderForm" from the form's source file for simplicity, this can be modified if required. If multiple tests want to instantiate the same form, a fixture should be used and the setup and teardown done here inside the test should be moved to the fixture's respective methods, but this is no longer C++Builder specific.
Note that Application->Run() is never called, and no GUI elements actually appear on the screen when executing the tests. I'm restricting tests to non-GUI methods of the GUI classes.
I'm currently working on a class assignment that requires the use of the CImg library. To be clear, the assignment is not linking the library into the program; The class is using it access the pixel data for later use in the heart of the assignment.
I'm working in Xcode (OS X 10.10). CImg (2.2.2) is installed from homebrew, and I've managed to navigate the weird way Xcode deals with search paths (added the header to the section), and have successfully-ish included CImg.
my full code is as below.
#include <iostream>
#define cimg_display 0 //I don't need X11 at all
#include "CImg.h"
using namespace cimg_library;
int main(int argc, const char * argv[]) {
// insert code here...
std::cout << "Hello, World!\n";
return 0;
}
However, I get 17 Compile-time errors from CImg.h, which are very unusual, and all of the form:
"No member named 't_normal' in the global namespace; did you mean simply 't_normal'?"
Thinking I might have received a bad download, I have attempted to redownload CImg, with no luck. I have also gotten to this same point with non-homebrew versions of CImg.
To verify the download, I also compiled the examples from the command line and they ran perfectly.
Is there a problem with CImg that I'm not aware of, a problem with Xcode that I'm not aware of, or is there something fundamental that I'm missing (definitely an option, my C-style programming is a little rusty) ?
halp pls.
Your code runs fine if you do this:
Create a new Xcode project, with:
type = "Command Line Tool"
language = "C++"
Then go to "Build Settings" and add the path to the directory containing CImg.h to your "User Header Search Paths"
I'm new to Qt creator. Yesterday, I followed the official instructions to configure OpenCV library but it failed. I tried everything on the Internet but it just didn't work. Detailed are listed as belows:
test code is simple, I only want to ensure whether the library works:
#include <iostream>
#include <opencv2/opencv.hpp>
using namespace std;
int main(int argc, char *argv[])
{
cout << "Hello World!" << endl;
return 0;
}
My project configuration is like below :
I thought there might be a problem in debugger. I configure the debugger and I'm quite sure it's ok. The picture is here:
But it just doesn't work. When I click build and run, it says:
C1083: cannot open containing files: "opencv2/opencv.hpp": No such
file or directory.
What's strange is when I include <files> in the editor, the automatic code completion can detect the existence of the OpenCV library and hint after <opencv2/> that there are opencv.hpp, core.hpp .etc. and in the Include Hierarchy, the opencv.hpp exists.
So what might be the problem?
This is a somewhat noob question.. I am trying display opencv images in OpenFrameworks. I am not using codeblocks or any specific IDE. I tried including the header file paths into the makefile, but was unable to run the code successfully.
For example, I have a test program such as
#include <stdio.h>
#include <opencv2/opencv.hpp>
#include <stdlib.h>
#include <iostream>
#include "ofMain.h"
#include "testApp.h"
#include "ofAppGlutWindow.h"
using namespace std;
using namespace cv;
int main(int argc, char** argv)
{
ofAppGlutWindow window;
ofSetupOpenGL(&window, 300, 300, OF_WINDOW);
ofRunApp( new testApp());
}
The flags in the makefile look like this
OF_FLAGS = -L../../../libs/openFrameworks/ -L../../../libs/openFrameworks/app
INCL = -I/usr/local/include
LIBS = -L/usr/local/lib -lopencv_core -lopencv_highgui
How do I exactly include the ofMain.h, testApp.h and ofAppGlutWindow.h paths into the makefile?
If you only want to use OpenCV with openFrameworks and don't want to do some super fancy custom stuff, I would recommend just looking at the open cv examples, which are bundled with openFrameworks. Just look in the <of folder>/examples/addons folder and try to compile opencvExample or opencvHaarFinderExample. If there are no Makefiles in the folder, try to generate them with the ofProjectGenerator. If everything is setup right, there is no need for manually change config.make or the Makefile of an example.
If the examples are the right direction for you, copy them, rename them and start your own project out of this.
Make sure the libs folder of ofxOpenCV is included in Build Settings > Search Paths > Header Search Paths.
In case it's not obvious, click on your XCode project in the upper left, then in the horizontal menu near the top, click on Build Settings and scroll down to Search Paths. Double click inside the value field for Header Search Paths and add ../../../addons/ofxOpenCV/libs. Lastly, set the dropdown on the right to recursive.
I am trying to learn c++ but most of the tutorials and books I have read or looked up teaches you this...
(I am assuming like most tutorials, they are teaching in the beginning to code either in win32 console or CLR console. In either case the following does not work.)
#include <iostream>
int main( )
{
std::cout << "Hello World\n";
return (0);
}
The IDE that i have is Visual C++ 2008 Express edition and they accept code like this
#include "stdafx.h"
int _tmain(int argc, _TCHAR* argv[])
{
return 0;
}
Or like this
#include "stdafx.h"
using namespace System;
int main(array<System::String ^> ^args)
{
Console::WriteLine(L"Hello World");
return 0;
}
Honestly I do not no the difference in none of these and I am not sure if I should just download a older compiler so that it works. If someone can tell me what the difference in these are and where to go from there. That will help tremendously. Thanks
[Edited]
I am trying to do a simple hello world. But I get the error "system can not find path specified." I have screenshot that shows what the error looks like. It also is saying that my project is out of date when I clearly save the file before I build it. Apparently it can not find the executable file. I went to the debug fold and did not see any .exe file.
[Edited]
Ok, now When I try to build the project I get the following errors
1>------ Rebuild All started: Project: test, Configuration: Debug Win32 ------
1>Deleting intermediate and output files for project 'test', configuration 'Debug|Win32'
1>Compiling...
1>stdafx.cpp
1>Compiling...
1>test.cpp
1>c:\users\numerical25\desktop\test\test\test.cpp(1) : warning C4627: '#include <iostream>': skipped when looking for precompiled header use
1> Add directive to 'stdafx.h' or rebuild precompiled header
1>c:\users\numerical25\desktop\test\test\test.cpp(6) : error C2653: 'std' : is not a class or namespace name
1>c:\users\numerical25\desktop\test\test\test.cpp(6) : error C2065: 'cout' : undeclared identifier
1>Build log was saved at "file://c:\Users\numerical25\Desktop\test\test\Debug\BuildLog.htm"
1>test - 2 error(s), 1 warning(s)
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========
Here is the code I used
#include <iostream>
#include "stdafx.h"
int main( )
{
std::cout << "Hello World\n";
return (0);
}
Note: I tried using it with and without the #include "stdafx.h" When I tried it without the #include "stdafx.h", it said I might be missing it.
Not sure what you're asking. The first two examples you gave are valid C++ programs that should (will) compile with VC++. The third example is a C++/CLI program that must be compiled with the /CLR compiler switch (this is called Managed C++).
EDIT: Adding more specific information (from a comment below):
The first two examples are standard (native) C++ (albeit, the second example has MS-proprietary macros). They compile to native code. The third is C++/CLI (a "managed" extension to C++). It compiles to managed (.NET) code. Only the third snippet interacts with the .NET framework in any way. All three are absolutely buildable and runnable using the appropriate projects in VS 2008 (no command line necessary)!
Based on your latest update, it looks like you have probably modified some project properties and changed some paths. The app is building, but when you try to run it via VS (you should do this with <Ctrl>+F5, by the way), the executable cannot be found (there are several ways you could have messed this up by changing or playing with various settings).
Please note the difference between building and running. Building is the process of compiling and linking your source code. Running is launching the resulting executable. You seem to be confused between these (judging from your complaints about the "...out of date" dialog box). It is normal to get the "...out of date" dialog box if you try to run without rebuilding after you have made a change to the project (even if that change is saved). Just make sure you click "yes." You need to build the project before you can run it.
My recommendation is to completely delete your project and solution. Create a new empty project, as suggested elsewhere in this now-very-heavyweight thread, and don't modify any project settings. If this doesn't work, something is seriously wrong!
ANOTHER EDIT: Just for completion, since this question kept changing:
As others have already pointed out, your ultimate problem with the first snippet is the use of precompiled headers (PCH). PCH are turned on by default in new VS C++ projects. Their purpose is to speed compilation when many implementation files include the same set of headers -- preventing the compiler from having to parse the header files for each compilation unit.
You have three options:
(Recommended) Disable PCH -- Project Properties --> Configuration Properties --> C/C++ --> Precompiled Headers: Set Create/Use Precompiled Header to Not Using Precompiled Headers. (You don't need to do anything with the "stdafx.h" file or the #include for it.)
Place your commonly used #includes in "stdafx.h". In your case, you would put #include <iostream> in "stdafx.h".
Place your #includes after `#include "stdafx.h". Microsoft requires that the "stdafx.h" be the first included file in a compilation unit.
A minor point, which I don't see elsewhere in the answers: When using precompiled headers, such as your stdafx.h, you need to include them first. Change it to:
#include "stdafx.h"
#include <iostream>
and that should fix the errors about it.
Alternatively, it may be easier to simply switch off precompiled headers: Project > Properties > Configuration Properties > C/C++ > Precompiled Headers > Switch first option to "Not using precompiled headers". They can be useful for big projects but will just be awkward and annoying while you're learning, since they have extra rules (like this "must be included first") which aren't requirements of standard C++ .
The "difference" is pedantic. The latter are just Microsoft-specific entry points.
As you are learning C++, I recommend you use a compiler, and preferably an operating system that lets you focus on C++, and not the platform. For this I recommend g++, on an Linux distribution such as Ubuntu.
Try this tutorial, there are many others that are similar that quickly let you overcome being tied to the tools, and focus on C++.
int main();
int main(int argc, char* argv[]);
These are standard C++.
int _tmain(int argc, _TCHAR* argv[]);
int wmain(int argc, wchar_t* argv[]);
These are Windows-specific to handle Unicode arguments. See What is the difference between _tmain() and main() in C++?.
int main(array<System::String^>^ args);
This is not C++. This is C++/CLI.
For best portability, always use the first form.
Also,
int main(int argc, char** argv, char** envp);
This is a usually seen POSIX extension. Windows supports this form of main too. The envp means (pointer to) environment variables.
int main(int argc, char** argv, char** envp, char** apple);
This is for Mac only, obviously.
void main();
And this is wrong (nonstandard, some compilers (e.g. gcc) will reject it).
Visual C++ Express will compile the first example just fine.
However, you need to ensure the proper project settings:
Create an "Empty Project"
"Add a new item..." to the project via the "Project" menu. Select C++ (.cpp) file.
Copy/Paste code into new file
Press F5 to compile and run.
When "Project is out of date" dialog appears, press "Yes" (build the project)
The steps above ensure VC++ Express does not treat your file as a special Win32/Windows console application.
EDIT: added additional step 5 to prevent "Can't find..." dialog.
I managed to get the same dialog by making sure the exe file does not exist, and answering "No" to the build dialog. With a clean, empty project the exe file does not exist yet. It must be built first. If you answer "no" don't build it, VC++ dutifully does not build the exe and later complains about not being able to find it when it tries to run it later.
As STingRaySC pointed out, all three of your examples will compile in VC2008 express; it's just that examples 2 and 3 are what VC2008 Express will load up initially when you create a project (one of the examples is for Managed C++, as STingRaySC mentioned).
You can just delete the code in your second example (the C++ Win32 Console Application project) and paste in the more standard hello world program from your first example. It should compile and run just fine in VC2008 Express - it did for me.
I. Precompiled header
#include "stdafx.h"
is some kind of tricky stuff that comes your way.
If you create a project VC will normally switch on precompiled header.
This means that one header stdafx.h is created which is compiled only once.
This is done to speed up compile time in big environments. If you start C++
it will confuse you.
If you use stdafx.h it has to be the first header in the cpp file.
II. Unicode (Utf16)
int _tmain(int argc, _TCHAR* argv[])
Microsoft uses UTF16 to implement unicode strings.
This means you get two versions of main.
int main(int argc, char* argv[])
int main(int argc, wchar_t* argv[])
This is also confusing if you start.
To simply start you can use whatever editor you want.
Create the file.
Open a Visdual studio 2008 command prompt
cl main.cpp
main.exe
and you will see Hello World using code from books.
Afterwards try to understand some of the settings of VC.
But you should always use an empty project.
Else you have to care about stdafx, UNICODE, ...
_tmain with the _TCHAR argv is the way the C runtime allows you to handle unicode. If _UNICODE is defined, then _tmain will expand to wmain, and the _TCHAR argument will be of type wchar_t. If _UNICODE is not defined, then _tmain will expand to main, which will be the ANSI standard.
Therefore, so long as _UNICODE is not defined, the second snippet you posted is compliant with the standard.
Lots of waxing lyrical and some misinformation for you sift through already, but I suggest following wonsungi's advice. But to clarify his advice:
File->New->Project
Select Project Type "Win32", then Template "Win32 Console Project"
Give the project a name and location
OK
Select "Application Settings"
Check "Empty Project"
In the "Solution Explorer", right click the "Sources" folder, then Add->New Item
Type the name of the file, in the "name" box using a .cpp extension (you can ignore the templates if you wish).
Enter your code in the new file.
Woot!! I figured it out!!! Below is my original code
#include <iostream>
int main( )
{
std::cout << "Hello World\n";
return (0);
}
It was missing the header file #include "stdafx.h" . So I had to include it in there so I added it like this
#include <iostream>
#include "stdafx.h"
int main( )
{
std::cout << "Hello World\n";
return (0);
}
I was still getting an error like what you see in my edited question at the bottom. So What I did is I took #include and added it in my header file and then it worked!!!!!
Even the the books and alot of tutorials show to add #include to the actual cpp, for some reason in express edition I had to add it to header for it to work. I don't know WHY but it's a solution and now it works.
Download and install Dev-C++ on your system. If the code doesn't work on Visual C++, try it out on Dev-C++ (which uses the GCC compiler). You may get the same results or a different error message. Whenever you get an error message you don't understand, do a Internet search for the error message.