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How to run a C++ code in Qt?

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  • S SGaist
    24 Nov 2015, 09:43

    Again, you have multiple main function, that's the first problem to solve. Why do you have more than one ?

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    Rela
    wrote on 25 Nov 2015, 08:50 last edited by
    #20

    @SGaist
    You mean the "main.cpp" and "mainwindow.cpp" ?
    If so, this is the same I did before with Qt5.4.1. There were the same main functions and gave the results in "Application Output".
    I create a new project in Qt creator:
    “New Project” >> “Qt Widgets Application” >> (Class name) “MainWindow” & (Base class) "QMainWindow" >> "Next" and "Finish" this application window:New Project
    After that I added .cpp and .h files of the C++ code using “Add existing Files”.

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      jsulm
      Lifetime Qt Champion
      wrote on 25 Nov 2015, 10:03 last edited by
      #21

      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.

      https://forum.qt.io/topic/113070/qt-code-of-conduct

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        Rela
        wrote on 25 Nov 2015, 12:44 last edited by Rela
        #22

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

        J 1 Reply Last reply 25 Nov 2015, 13:34
        0
        • R Rela
          25 Nov 2015, 12:44

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

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          jsulm
          Lifetime Qt Champion
          wrote on 25 Nov 2015, 13:34 last edited by
          #23

          @Rela You should remove one of them.

          https://forum.qt.io/topic/113070/qt-code-of-conduct

          R 1 Reply Last reply 25 Nov 2015, 13:47
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          • J jsulm
            25 Nov 2015, 13:34

            @Rela You should remove one of them.

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            Rela
            wrote on 25 Nov 2015, 13:47 last edited by Rela
            #24

            @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" ?

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              jsulm
              Lifetime Qt Champion
              wrote on 25 Nov 2015, 13:50 last edited by
              #25

              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.

              https://forum.qt.io/topic/113070/qt-code-of-conduct

              R 1 Reply Last reply 25 Nov 2015, 14:21
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              • J jsulm
                25 Nov 2015, 13:50

                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.

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                Rela
                wrote on 25 Nov 2015, 14:21 last edited by
                #26

                @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.

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                • S Offline
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                  SGaist
                  Lifetime Qt Champion
                  wrote on 25 Nov 2015, 15:36 last edited by
                  #27

                  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.

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                  R 1 Reply Last reply 1 Dec 2015, 11:29
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                  • S SGaist
                    25 Nov 2015, 15:36

                    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.

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                    Rela
                    wrote on 1 Dec 2015, 11:29 last edited by Rela 12 Jan 2015, 11:34
                    #28

                    @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

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                    • S Offline
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                      SGaist
                      Lifetime Qt Champion
                      wrote on 1 Dec 2015, 11:33 last edited by
                      #29

                      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.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      R 2 Replies Last reply 1 Dec 2015, 12:03
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                      • S SGaist
                        1 Dec 2015, 11:33

                        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.

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                        Rela
                        wrote on 1 Dec 2015, 12:03 last edited by
                        #30
                        This post is deleted!
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                        • S SGaist
                          1 Dec 2015, 11:33

                          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.

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                          Rela
                          wrote on 1 Dec 2015, 12:13 last edited by
                          #31

                          @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

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                          • S Offline
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                            SGaist
                            Lifetime Qt Champion
                            wrote on 1 Dec 2015, 12:20 last edited by
                            #32

                            You need to install the debugger for MSVC

                            Interested in AI ? www.idiap.ch
                            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                            R 1 Reply Last reply 1 Dec 2015, 13:00
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                            • S SGaist
                              1 Dec 2015, 12:20

                              You need to install the debugger for MSVC

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                              Rela
                              wrote on 1 Dec 2015, 13:00 last edited by
                              #33

                              @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

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                              • S Offline
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                                SGaist
                                Lifetime Qt Champion
                                wrote on 1 Dec 2015, 15:35 last edited by
                                #34

                                MSVC debugger can only be obtained from Microsoft website, here

                                Interested in AI ? www.idiap.ch
                                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                R 2 Replies Last reply 2 Dec 2015, 10:34
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                                • S SGaist
                                  1 Dec 2015, 15:35

                                  MSVC debugger can only be obtained from Microsoft website, here

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                                  Rela
                                  wrote on 2 Dec 2015, 10:34 last edited by
                                  #35

                                  @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.

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                                  • S SGaist
                                    1 Dec 2015, 15:35

                                    MSVC debugger can only be obtained from Microsoft website, here

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                                    Rela
                                    wrote on 2 Dec 2015, 13:44 last edited by
                                    #36

                                    @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?

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                                    • S Offline
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                                      SGaist
                                      Lifetime Qt Champion
                                      wrote on 2 Dec 2015, 22:17 last edited by
                                      #37

                                      Did you implement anything in MainWindow ?

                                      Interested in AI ? www.idiap.ch
                                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                      R 1 Reply Last reply 3 Dec 2015, 11:27
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                                      • S SGaist
                                        2 Dec 2015, 22:17

                                        Did you implement anything in MainWindow ?

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                                        Rela
                                        wrote on 3 Dec 2015, 11:27 last edited by Rela 12 Mar 2015, 11:44
                                        #38

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

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                                        • S Offline
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                                          SGaist
                                          Lifetime Qt Champion
                                          wrote on 3 Dec 2015, 12:20 last edited by
                                          #39

                                          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.

                                          Interested in AI ? www.idiap.ch
                                          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                          R 1 Reply Last reply 3 Dec 2015, 13:41
                                          0

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