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How to run a C++ code in Qt?

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  • SGaistS SGaist

    You have to fix the includes in your O_PS* files so add the missing #include <stdio.h>

    RelaR Offline
    RelaR Offline
    Rela
    wrote on last edited by
    #103

    @SGaist
    Do I add #include <stdio.h> to "mainwindow.h" ? I added to all files one by one , but the same errors happen.
    Do I need to add #include "stdafx.h" or something else also?

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    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #104

      No, include them in your O_PS* files where suited.

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

      RelaR 1 Reply Last reply
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      • SGaistS SGaist

        No, include them in your O_PS* files where suited.

        RelaR Offline
        RelaR Offline
        Rela
        wrote on last edited by Rela
        #105

        @SGaist
        I copied the "O_PSA .H" and "O_PS .CPP" code in the "mainwindow.h" and "main.cpp" of the Qt project respevtively. I did add ```

        #include <stdio.h> 
        

        in either "mainwindow.h" or "main.cpp" files, but it gave the same errors

        kshegunovK 1 Reply Last reply
        0
        • RelaR Rela

          @SGaist
          I copied the "O_PSA .H" and "O_PS .CPP" code in the "mainwindow.h" and "main.cpp" of the Qt project respevtively. I did add ```

          #include <stdio.h> 
          

          in either "mainwindow.h" or "main.cpp" files, but it gave the same errors

          kshegunovK Offline
          kshegunovK Offline
          kshegunov
          Moderators
          wrote on last edited by kshegunov
          #106

          @Rela
          It must have taken you ages to delete those names ... Anyway, to use ostream, istream and other streams from the standard C++ library, you actually need to include the corresponding headers - stdio.h simply won't cut it. You need (depending on which classes you use) one of the *stream headers, e.g. #include <iostream>, #include <fstream> and so on. Additionally, these classes come in the std namespace so you'd need to expand that as well, for example.

          #include <iostream>
          
          using namespace std;
          
          // Only now the istream and ostream classes are available.
          

          Kind regards.

          Read and abide by the Qt Code of Conduct

          RelaR 1 Reply Last reply
          0
          • kshegunovK kshegunov

            @Rela
            It must have taken you ages to delete those names ... Anyway, to use ostream, istream and other streams from the standard C++ library, you actually need to include the corresponding headers - stdio.h simply won't cut it. You need (depending on which classes you use) one of the *stream headers, e.g. #include <iostream>, #include <fstream> and so on. Additionally, these classes come in the std namespace so you'd need to expand that as well, for example.

            #include <iostream>
            
            using namespace std;
            
            // Only now the istream and ostream classes are available.
            

            Kind regards.

            RelaR Offline
            RelaR Offline
            Rela
            wrote on last edited by Rela
            #107

            @kshegunov
            There are

            using namespace std;
            #include <iostream>
            #include <fstream>
            #include <ostream>
            

            in the "main.cpp" already. I added ```

            #include <stdio.h>
            

            in each file, but it gave the same error.

            kshegunovK 1 Reply Last reply
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            • RelaR Rela

              @kshegunov
              There are

              using namespace std;
              #include <iostream>
              #include <fstream>
              #include <ostream>
              

              in the "main.cpp" already. I added ```

              #include <stdio.h>
              

              in each file, but it gave the same error.

              kshegunovK Offline
              kshegunovK Offline
              kshegunov
              Moderators
              wrote on last edited by kshegunov
              #108

              @Rela said:

              There are ... in the "main.cpp" already.

              But obviously these headers are not present in mainwindow.h, whence the compile errors. The compiler doesn't know heck about ostream when processing the mainwindow.h and it's whining ...

              Kind regards.

              Read and abide by the Qt Code of Conduct

              RelaR 1 Reply Last reply
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              • kshegunovK kshegunov

                @Rela said:

                There are ... in the "main.cpp" already.

                But obviously these headers are not present in mainwindow.h, whence the compile errors. The compiler doesn't know heck about ostream when processing the mainwindow.h and it's whining ...

                Kind regards.

                RelaR Offline
                RelaR Offline
                Rela
                wrote on last edited by
                #109

                @kshegunov
                Thanks. Do you know what else I can do except adding ```

                #include <stdio.h>
                

                to the "mainwindow.h"?

                kshegunovK 1 Reply Last reply
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                • RelaR Rela

                  @kshegunov
                  Thanks. Do you know what else I can do except adding ```

                  #include <stdio.h>
                  

                  to the "mainwindow.h"?

                  kshegunovK Offline
                  kshegunovK Offline
                  kshegunov
                  Moderators
                  wrote on last edited by
                  #110

                  @Rela

                  Add the aforementioned headers to the mainwindow.h:

                  #include <iostream>
                  #include <fstream>
                  #include <ostream>
                  
                  using namespace std;
                  

                  Otherwise the compiler will not know what ostream is.

                  Read and abide by the Qt Code of Conduct

                  RelaR 1 Reply Last reply
                  0
                  • kshegunovK kshegunov

                    @Rela

                    Add the aforementioned headers to the mainwindow.h:

                    #include <iostream>
                    #include <fstream>
                    #include <ostream>
                    
                    using namespace std;
                    

                    Otherwise the compiler will not know what ostream is.

                    RelaR Offline
                    RelaR Offline
                    Rela
                    wrote on last edited by
                    #111

                    @kshegunov
                    Done, but here are the errors cleaned again ;)

                    kshegunovK 1 Reply Last reply
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                    • RelaR Rela

                      @kshegunov
                      Done, but here are the errors cleaned again ;)

                      kshegunovK Offline
                      kshegunovK Offline
                      kshegunov
                      Moderators
                      wrote on last edited by
                      #112

                      @Rela
                      I'm sorry but I have no idea what's happening, with the deletions and without a complete code snippet this is just turning into a guessing game. Not to mention the preprocessor directives, whose expansions I have no way of deducing. The errors have obviously changed and they are at compile-time, so focus on that and try to resolve the type mismatches.

                      Read and abide by the Qt Code of Conduct

                      RelaR 1 Reply Last reply
                      0
                      • kshegunovK kshegunov

                        @Rela
                        I'm sorry but I have no idea what's happening, with the deletions and without a complete code snippet this is just turning into a guessing game. Not to mention the preprocessor directives, whose expansions I have no way of deducing. The errors have obviously changed and they are at compile-time, so focus on that and try to resolve the type mismatches.

                        RelaR Offline
                        RelaR Offline
                        Rela
                        wrote on last edited by
                        #113

                        @kshegunov
                        The problem is not related to the code. The C++ code works properly in MV and also it worked in Qt creator before and gave the results in "Application Outputs" with Qt5.5 and MV 2013. The problem happened, when I start working with MV 2015 and Qt5.6 beta.
                        I just did the previous way and added all C++ files to the Qt project files. Do you have any idea about the ```

                        error: dependent '..\C++' does not exist.
                        
                        kshegunovK 1 Reply Last reply
                        0
                        • RelaR Rela

                          @kshegunov
                          The problem is not related to the code. The C++ code works properly in MV and also it worked in Qt creator before and gave the results in "Application Outputs" with Qt5.5 and MV 2013. The problem happened, when I start working with MV 2015 and Qt5.6 beta.
                          I just did the previous way and added all C++ files to the Qt project files. Do you have any idea about the ```

                          error: dependent '..\C++' does not exist.
                          
                          kshegunovK Offline
                          kshegunovK Offline
                          kshegunov
                          Moderators
                          wrote on last edited by
                          #114

                          @Rela
                          I have never seen that error, but if I had to guess probably a folder can't be found by qmake. Inspect your project file, and make sure all folders/files exist. Then rerun qmake and then do a full rebuild. Additionally, don't use backslashes for your paths when working with qmake, use *nix-style paths, for example: C:/somefolder/somefile.cpp

                          Read and abide by the Qt Code of Conduct

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                          • SGaistS Offline
                            SGaistS Offline
                            SGaist
                            Lifetime Qt Champion
                            wrote on last edited by
                            #115

                            Do you have something containing "C++" anywhere in your .pro file ?

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

                            RelaR 1 Reply Last reply
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                            • SGaistS SGaist

                              Do you have something containing "C++" anywhere in your .pro file ?

                              RelaR Offline
                              RelaR Offline
                              Rela
                              wrote on last edited by
                              #116

                              @SGaist
                              Yes, I had something like this in PS8, because I added the C++ project header and source files through the "../C++ projects/po... /" path. But, now I removed the space of "C++ projects" (because maybe it makes problem), and changed the path withoutspace. PS10 Qt project .pro file is this
                              Now the error is this

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                              • jsulmJ Offline
                                jsulmJ Offline
                                jsulm
                                Lifetime Qt Champion
                                wrote on last edited by
                                #117

                                What is char.h?

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

                                RelaR 1 Reply Last reply
                                0
                                • jsulmJ jsulm

                                  What is char.h?

                                  RelaR Offline
                                  RelaR Offline
                                  Rela
                                  wrote on last edited by Rela
                                  #118

                                  @jsulm
                                  It was

                                  #include <tchar.h>
                                  

                                  in the C++ code, but it had given the errors like

                                  'void PS... (char *)': cannot convert argument 1 from 'const char [37]' to 'char *'
                                  

                                  and I changed it to "char".
                                  I think its related to the main function in "main.cpp"

                                  int main(int argc, char* argv[])
                                  {
                                  
                                  kshegunovK 1 Reply Last reply
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                                  • jsulmJ Offline
                                    jsulmJ Offline
                                    jsulm
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #119

                                    How is it related to main?
                                    char is a native data type in C and C++, you do not have to include any header file to use it. So just remove this include.
                                    This error:

                                    'void PS... (char *)': cannot convert argument 1 from 'const char [37]' to 'char *'
                                    

                                    You got probably because you're passing a const char string as parameter to a function which expects a non const char string:

                                    void PS... (char *param);
                                    then you call
                                    PS...("a string");
                                    

                                    Do it like this:

                                    char *param = "a string";
                                    PS...(param);
                                    

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

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                                    • RelaR Rela

                                      @jsulm
                                      It was

                                      #include <tchar.h>
                                      

                                      in the C++ code, but it had given the errors like

                                      'void PS... (char *)': cannot convert argument 1 from 'const char [37]' to 'char *'
                                      

                                      and I changed it to "char".
                                      I think its related to the main function in "main.cpp"

                                      int main(int argc, char* argv[])
                                      {
                                      
                                      kshegunovK Offline
                                      kshegunovK Offline
                                      kshegunov
                                      Moderators
                                      wrote on last edited by
                                      #120

                                      @Rela

                                      'void PS... (char *)': cannot convert argument 1 from 'const char [37]' to 'char *'

                                      The error is because you're passing const char * const to a function expecting char * and the compiler doesn't know how to (safely) convert the argument. My advice is: rework your function to accept non-mutable arguments if possible, if not - fix the type mismatch. @jsulm already pointed out that you shouldn't include headers you're not going to need, unless massive compilation times is something you're after.

                                      Kind regards.

                                      Read and abide by the Qt Code of Conduct

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                                      • RelaR Offline
                                        RelaR Offline
                                        Rela
                                        wrote on last edited by Rela
                                        #121

                                        Hi, the previous error was solved. I wanted to have a C++ code results in widget. For reminding in brief, I created a Qt widget project, and I added the C++ code including header and source files to the project. I copied the main.cpp C++ codes in the Qt main.cpp file.

                                        The error was ```

                                        void PS... (char *)': cannot convert argument 1 from 'const char [37]' to 'char *
                                        

                                        I changed the definition of the function:

                                        void PS... (char *_sth)
                                        

                                        to

                                        void PS... (const char *_sth) 
                                        

                                        and it doesn't give the error. But, now I want to have some values as result in Application Output , but instead of the non-zero values, they are all zero.
                                        The input data are read from a model.txt file. The path of the text file was also added in the "project" > run of "Desktop Qt 5.6 MSVC2015 64 bit" > "Arguments". Do you know if it is related to the reading input data or not?

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                                        • jsulmJ Offline
                                          jsulmJ Offline
                                          jsulm
                                          Lifetime Qt Champion
                                          wrote on last edited by
                                          #122

                                          How do you read model.txt file?
                                          Is this file found?
                                          Do you have any errors while reading it?
                                          Why don't just debug and see what happens?

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

                                          RelaR 1 Reply Last reply
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