How to run a C++ code in Qt?

jsulm

SGaist means the C/C++ main function:

int main(int argc, char** argv)
{
...
}

An application can only have one main function, as the compiler error says you have two of them.

Rela

I have one "int main(int argc, char argv[])
{ ..."* function in "O_PS .cpp" file, and one main function in "main.cpp" file. Qt

jsulm

@Rela You should remove one of them.

Rela

@jsulm
Could you explain how? The main function of "O_PS .cpp" is my C++ code, do I delete:
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();

return a.exec();

} in "main.cpp" ?

jsulm

I don't know which of them you have to remove. I don't know your code and I don't know what you want to do. You have to decide which of them is the right one and then just delete the other. You just cannot have more than one entry point (more than one main function) in a C/C++ program.

Rela

@jsulm
I definitely need my C++ code, because everything to get the results is in the code, but when I create a new project in Qt, the "main.cpp" file is also created. If I right click on it and "Remove File" do I need add this code somewhere?

I had Qt5.4.1 before, and it gave results in "Application output" previously using “Desktop Qt5.4 MinGW” with the same main functions.

SGaist

If you already have a main function that does everything then no. Just keep this in mind: having your main function in a file not named main.cpp is pretty unusual for an application, not forbidden, just unusual. Beware of maintenance nightmare.

Rela

@SGaist

I created another project file, and added the C++ files, but instead of adding the code .cpp file I copied it in "main.cpp" file. The only change I made was that copied the

QApplication a(argc, argv);
    MainWindow w;
    w.show();

After
int main(int argc, char *argv[])
{
. So, now there is only one main function in "main.cpp".

After that I added the text file by "Argument", using MinGW 32bit, gives this "Runtime Library" error: MinGW 32bit I read maybe its because MinGW is 32bit and I need to use 64 bit as compiler.
And used "Desktop Qt5.5.1 MSVC 2013 64 bit" , it gives this error: MSVC 64bit

SGaist

Run it through the debugger, you're doing something fishy in your code. Throwing a bad alloc means that you are trying to allocated more memory than it's available. It might pass on 64bit (not the same memory limits) but if it does, it means that you are doing something else that is wrong and makes your application crash.

Rela

This post is deleted!

Rela

@SGaist
When I click on MSVC to debug MSVC and "F5", it gives this error: No engine
When I use MinGW and "F5", it gives this error: MinGW

SGaist

You need to install the debugger for MSVC

Rela

@SGaist
In "Maintenance Tool.exe" these components were chosen. components Do I need to mark "Windows Runtime" also?
In "Build & Run", there is one debugger, if it should be added manually, from which folder I have to select it? Debugger

SGaist

MSVC debugger can only be obtained from Microsoft website, here

Rela

@SGaist
Thanks, should I install SDK or WDK?
I did search,but it is said that CDB goes with Visual C++, but there is not download link for CDB.

Rela

@SGaist
I installed Windows SDK and chose all components including "debugging tools for windows". Now, in Tools -> Options -> Build & Run -> Debuggers, I see the two paths for CDB. In "Kit" I chose "Desktop Qt5.5.1 MSVC2013 64bit" and from "Debugger" combo, the CDB.
I debug the program with it, and it doesn't give the previous error, but first open the mainwindow.ui and then shows "Debugging starts" in "Application Output" and Compile Output.
As I wrote before, instead of adding the (C++code.cpp) file I copied the code in "main.cpp" file to have one main fucntion. The only change I made was that copied the

QApplication a(argc, argv);
    MainWindow w;
    w.show();

After
int main(int argc, char *argv[])
{
in my C++ code. How can I see the results (which are some numbers) in mainwindow.ui?

SGaist

Did you implement anything in MainWindow ?

Rela

@Rela
Yes, its an algorithm here written in C++.

SGaist

I can't really read it because of all the whited out parts. But the first thing I'd do is check that you don't do anything funky in there. Remove what's not related to your algorithm from main and try to run that. Once it's good, bring back the Qt parts.

Rela

@SGaist
Sorry for white space, I have to remove some function names. The algorithm is 2820 lines, and I think each line is needed to output the result. Do you mean i remove the algorithm completely and just remain
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();}

in main.cpp
I did that and the here is the output.