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C++ struct function with return struct ...

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  • m.sueM m.sue

    Hi,
    "result" is a local variable in "afunc". You cannot expect it to be known outside of "afunc". This is no restriction of Qt but a feature of the C++ language. But you can write something like this:

    a result=afunc(myvalue);
    myvar1 = result.x;
    myvar2 = result.y;
    

    -Michael.

    gfxxG Offline
    gfxxG Offline
    gfxx
    wrote on last edited by gfxx
    #8

    @m.sue Tanks A lot I have just read in an ebook this peculiarity of the struct .... I have many elements struct each one with a calculation and a return .... something like these:

    struct a{
    int x;
    double y;
    cv::Point cerr0;
    cv::Point cerr1;
    cv::Point cerr2;
    cv::Point cerr3;
    cv::Point result1() { return /* some long calculation*/};
    cv::Point result2() {return  /* some long calculation*/};
    cv::Point result3() {return  /* some long calculation*/};
    
    }
    
    ........
    
    afunc (cv::Point cerr0){  /* so in my file.cpp i can write these*/
    some_value0 = afunc.result1;
    some_value1 = afunc.result2;
    some_value2 = afunc.result3;
    
    

    In my case I think is a little bit more long as I expect .... :( ..so I try your suggest to try to simplify my function ...

    Regards
    Giorgio

    bkt

    gfxxG 1 Reply Last reply
    0
    • gfxxG gfxx

      @m.sue Tanks A lot I have just read in an ebook this peculiarity of the struct .... I have many elements struct each one with a calculation and a return .... something like these:

      struct a{
      int x;
      double y;
      cv::Point cerr0;
      cv::Point cerr1;
      cv::Point cerr2;
      cv::Point cerr3;
      cv::Point result1() { return /* some long calculation*/};
      cv::Point result2() {return  /* some long calculation*/};
      cv::Point result3() {return  /* some long calculation*/};
      
      }
      
      ........
      
      afunc (cv::Point cerr0){  /* so in my file.cpp i can write these*/
      some_value0 = afunc.result1;
      some_value1 = afunc.result2;
      some_value2 = afunc.result3;
      
      

      In my case I think is a little bit more long as I expect .... :( ..so I try your suggest to try to simplify my function ...

      Regards
      Giorgio

      gfxxG Offline
      gfxxG Offline
      gfxx
      wrote on last edited by
      #9

      @gfxx ...NOT WORK ...

      my real code:

      /******************in my file.h*-***********************/
      
       FindAngleCPointTarghet FindCentPoint( cv::Point2f Square_Points[4], bool a, bool b, bool c, bool d)
          {
      
              FindAngleCPointTarghet FindTarghet;
      
              F_lung1 = 0;
              F_lung2 = 0;
              F_lung3 = 0;
              F_lung4 = 0;
              F_lung5 = 0;
              F_barix = 0;
              F_bariy = 0;
              F_intbarix = 0;
              F_intbariy = 0;
              F_bariangle = 0;
              bool choose0 = false, choose1 = false, choose2 = false, choose3 = false;
      
              F_lung1 = std::pow((std::pow((Square_Points[0].x - Square_Points[1].x),2) + std::pow((Square_Points[0].y - Square_Points[1].y),2)), 0.5);
              F_lung2 = std::pow((std::pow((Square_Points[1].x - Square_Points[2].x),2) + std::pow((Square_Points[1].y - Square_Points[2].y),2)), 0.5);
      
              if (F_lung2 > F_lung1)
              {
                  F_lung3 = F_lung2;
                  F_lung4 = std::pow((std::pow((-Square_Points[1].x + Square_Points[2].x),2) + std::pow((0),2)), 0.5);
                  F_lung5 = std::pow((std::pow((-Square_Points[1].y + Square_Points[2].y),2) + std::pow((0),2)), 0.5);
                  F_barix = ((Square_Points[0].x + Square_Points[1].x + Square_Points[2].x + Square_Points[3].x)/4);
                  F_bariy = ((Square_Points[0].y + Square_Points[1].y + Square_Points[2].y + Square_Points[3].y)/4);
                  F_intbarix = round(F_barix);
                  F_intbariy = round(F_bariy);
                  F_bariangle = (std::atan2((Square_Points[2].y - Square_Points[1].y),(Square_Points[2].x - Square_Points[1].x))*180.00/3.1415926535);
                  F_centrale = cv::Point(F_intbarix, F_intbariy);
                  F_bariangle_template = F_bariangle;
                  if(a)
                  {
      
      ..................
      /*the calculation proceed for 180 row with the same variable declared here ... the result ( FindTarghet.Get_centrale etc)  value change if a-b or a-d or etc etc bool value is true or false ....*/
      ..................
      
              FindTarghet.Get_centrale = F_centrale;
              FindTarghet.Get_mezzo_rect_risc = F_mezzo_rect_risc;
              FindTarghet.Get_mezzo_rect_risc1 = F_mezzo_rect_risc1;
              FindTarghet.Get_mezzo_rect_risc_pt2 = F_mezzo_rect_risc_pt2;
              FindTarghet.Get_mezzo_rect_risc_pt3 = F_mezzo_rect_risc_pt3;
              FindTarghet.X_Point = F_intbarix;
              FindTarghet.Y_point = F_intbariy;
              FindTarghet.Angle = F_bariangle_template;
              FindTarghet.Major_Side1 = false;
              FindTarghet.Major_Side2 = false;
              FindTarghet.Get_Upper_Half_Square  = false;
              FindTarghet.Get_Lower_Half_Square = false;
      
              return FindTarghet;
      
      
      /* than in my file.ccp*******************/
      
      FindAngleCPointTarghet TarghetResutl = FindCentPoint(rect_points, targhet_verticale, targhet_orizzontale);
      centrale =  TarghetResutl.Get_centrale;
      mezzo_rect_risc = TarghetResutl.Get_mezzo_rect_risc;
      mezzo_rect_risc1 = TarghetResutl.Get_mezzo_rect_risc1;
      mezzo_rect_risc_pt2 = TarghetResutl.Get_mezzo_rect_risc_pt2;
      mezzo_rect_risc_pt3 = TarghetResutl.Get_mezzo_rect_risc_pt3;
      intbarix = TarghetResutl.X_Point;
      intbariy = TarghetResutl.Y_point;
      bariangle = TarghetResutl.Angle;
      
      /***********the error .... 380 error signed .... a memeory allocation id/name problem I think****************/
      (.bss+0x120):-1: error: multiple definition of `F_lung4'
      (.bss+0x128):-1: error: multiple definition of `F_lung3' .... etc etc.... all identical error but for all variable used during calculation ....
      
          }
      

      I'm explain my better ... I try to make in file.h a struct function with struct return value .... As you see

      bkt

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      0
      • mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by mrjj
        #10

        If you include data in .h file, you can get this error
        multiple definition of XXX

        Im not sure why this is so complex.

        --
        MYS.h

        struct MyStruct { // DEFINE
        int Value;
        };

        MyStruct MyFunc(); // DEFINE

        --
        MYS.cpp

        MyStruct MyFunc() { // IMPLEMENT
        MyStruct localcopy;
        localcopy.Value=100;
        return localcopy;
        }

        -- in some file--
        #include "MYS.h"

        void buttonClick() {
        MyStruct usedhere = MyFunc(); // USING

        }

        1 Reply Last reply
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        • gfxxG Offline
          gfxxG Offline
          gfxx
          wrote on last edited by gfxx
          #11

          MYS = MYQThread so....

          --
           MYQThread .h
          
          struct MyStruct { // DEFINE
          int Value;
          };
          /* now I try to do these*/
          MyStruct MyFunc(with  parameter){some calculation with pnota bene arameter and some other local variable}; // DEFINE
          --
           MYQThread .cpp
          
          MyStruct MyFunc() { // IMPLEMENT /* so your answer is : " in these local copy make your calculation" ... is right?*/
          MyStruct localcopy;
          localcopy.Value=100;
          return localcopy;
          }
          
          -- in these  MYQThread.cpp-- /* but my file.h and file.cpp is the same so is not possible do these ....*/
          #include " MYQThread .h"
          
          void buttonClick() {
          MyStruct usedhere = MyFunc(); // USING
          
          }
          

          If I understand well your reply you think mi struct function is utilize in other part of my app ... but is define in QThread.h and implement + utilized in QThread.cpp

          Regards
          Giorgio

          Note:
          @mrjj perhaps your answer sounds like you'd better build a class that a struct func ....

          bkt

          1 Reply Last reply
          0
          • mrjjM Offline
            mrjjM Offline
            mrjj
            Lifetime Qt Champion
            wrote on last edited by mrjj
            #12

            make sure that
            MYQThread .cpp

            MyStruct MyFunc(same params as in .h) {...}

            No sure i understand
            /* but my file.h and file.cpp is the same so is not possible do these*/

            why is file.cpp and file.h the same?

            Also for the use

            void buttonClick() {
            MyStruct usedhere = MyFunc( ACTUAL PARAMETERS); // USING

            }

            1 Reply Last reply
            0
            • gfxxG Offline
              gfxxG Offline
              gfxx
              wrote on last edited by
              #13
              /***********MYQThread .h*****************/
              
              struct FindACPTarghet{
                  cv::Point2f Square_Points[4];
                  bool Find_Upper_Half_Square;
                  bool Find_Lower_Half_Square;
                  cv::Point Get_centrale;
                  cv::Point Get_mezzo_rect_risc;
                  cv::Point Get_mezzo_rect_risc1;
                  cv::Point Get_mezzo_rect_risc_pt2;
                  cv::Point Get_mezzo_rect_risc_pt3;
                  double X_Point;
                  double Y_point;
                  double Angle;
                  bool Major_Side1;
                  bool Major_Side2;
                  bool Get_Upper_Half_Square;
                  bool Get_Lower_Half_Square;
                  //Get_Angle_Central_Point_Targhet GetDataTarghet;
              }/*FindCentPoint*/;
              
              class datathread : public QThread
              {
                      Q_OBJECT
              public:
                  explicit datathread(QObject *parent = 0, bool bthw = false);
                  void run();
                  bool Stop;
              
                  FindACPTarghet FindCentPoint( cv::Point2f Square_Points[4], bool Find_Upper_Half_Square, bool Find_Lower_Half_Square);
              
              /***********MYQThread .cpp*****************/
              
              FindACPTarghet FindCentPoint( cv::Point2f Square_Points[4], bool Find_Upper_Half_Square, bool Find_Lower_Half_Square)
              {
              
                  FindACPTarghet FindTarghet;  <----------------------------------------
              
                  F_lung1 = 0;
                  F_lung2 = 0;
                  F_lung3 = 0;
                  F_lung4 = 0;
                  F_lung5 = 0;
                  F_barix = 0;
                  F_bariy = 0;
                  F_intbarix = 0;
                  F_intbariy = 0;
                  F_bariangle = 0;
                  bool choose0 = false, choose1 = false, choose2 = false, choose3 = false;
              
                  F_lung1 = std::pow((std::pow((Square_Points[0].x - Square_Points[1].x),2) + std::pow((Square_Points[0].y - Square_Points[1].y),2)), 0.5);
                  F_lung2 = std::pow((std::pow((Square_Points[1].x - Square_Points[2].x),2) + std::pow((Square_Points[1].y - Square_Points[2].y),2)), 0.5);
              
                  if (F_lung2 > F_lung1)
                  {..................
              ........................
              
                  FindTarghet.Get_centrale = F_centrale;  <--------------------------------- /*******************************undefined error reference**********************/
                  FindTarghet.Get_mezzo_rect_risc = F_mezzo_rect_risc;
                  FindTarghet.Get_mezzo_rect_risc1 = F_mezzo_rect_risc1;
                  FindTarghet.Get_mezzo_rect_risc_pt2 = F_mezzo_rect_risc_pt2;
                  FindTarghet.Get_mezzo_rect_risc_pt3 = F_mezzo_rect_risc_pt3;
                  FindTarghet.X_Point = F_intbarix;
                  FindTarghet.Y_point = F_intbariy;
                  FindTarghet.Angle = F_bariangle_template;
                  FindTarghet.Major_Side1 = false;
                  FindTarghet.Major_Side2 = false;
                  FindTarghet.Get_Upper_Half_Square  = false;
                  FindTarghet.Get_Lower_Half_Square = false;
              
                  return FindTarghet;
              
              }
              
              /***********MYQThread .cpp    qthread::run*****************/
              void datathread::run()   
              {
              ...
              ...
              ...
              
              FindACPTarghet OneTarghet = FindCentPoint(rect_points, true, false);
                                                centrale =  OneTarghet.Get_centrale;
                                                mezzo_rect_risc = OneTarghet.Get_mezzo_rect_risc;
                                                mezzo_rect_risc1 = OneTarghet.Get_mezzo_rect_risc1;
                                                mezzo_rect_risc_pt2 = OneTarghet.Get_mezzo_rect_risc_pt2;
                                                mezzo_rect_risc_pt3 = OneTarghet.Get_mezzo_rect_risc_pt3;
                                                intbarix = OneTarghet.X_Point;
                                                intbariy = OneTarghet.Y_point;
                                                bariangle = OneTarghet.Angle;
              
              

              Not understand very well why I can't use return with struct ....

              Regards
              Giorgio

              bkt

              1 Reply Last reply
              0
              • mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by
                #14

                But you can use struct as return. :)

                FindTarghet.Get_centrale = F_centrale;

                what is F_central?
                I dont see you define it ?
                so that would explain "undefined"

                gfxxG 1 Reply Last reply
                0
                • mrjjM mrjj

                  But you can use struct as return. :)

                  FindTarghet.Get_centrale = F_centrale;

                  what is F_central?
                  I dont see you define it ?
                  so that would explain "undefined"

                  gfxxG Offline
                  gfxxG Offline
                  gfxx
                  wrote on last edited by
                  #15

                  @mrjj mmm....

                  
                  /********* as global var in MYQThread .cpp*****************/
                  int F_intbarix = 0, F_intbariy = 0;
                  double F_lung1 = 0, F_lung11 = 0, F_lung2 = 0, F_lung3 = 0, F_lung4 = 0, F_lung5 = 0, F_barix = 0, F_bariy = 0, F_bariangle = 0, F_bariangle_template = 0;
                  int DeF_barix = 0, DeF_bariy = 0, DeF_bariangle = 0, DeF_bariangle_template = 0;
                  int X_mezzo_rect_risc = 0, Y_mezzo_rect_risc = 0, X_mezzo_rect_risc1 = 0, Y_mezzo_rect_risc1 = 0;
                  int X_mezzo_rect_risc_pt2 = 0, Y_mezzo_rect_risc_pt2 = 0, X_mezzo_rect_risc_pt3 = 0, Y_mezzo_rect_risc_pt3 = 0;
                  int DeF_Major_Side1 = 0, DeF_Major_Side2 = 0, DeF_Get_Upper_Half_Square = 0, DeF_Get_Lower_Half_Square = 0;
                  
                  cv::Point F_centrale = cv::Point(0 ,0); <------------------------------------------------------- /****** and use these variable into calculation and as result too... so i put it into return struc as you see****/
                  
                  cv::Point F_mezzo_rect_risc = cv::Point(0 ,0);
                  cv::Point F_mezzo_rect_risc1 = cv::Point(0 ,0);
                  cv::Point F_mezzo_rect_risc_pt2 = cv::Point(0 ,0);
                  

                  Regards
                  giorgio

                  bkt

                  gfxxG 1 Reply Last reply
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                  • gfxxG gfxx

                    @mrjj mmm....

                    
                    /********* as global var in MYQThread .cpp*****************/
                    int F_intbarix = 0, F_intbariy = 0;
                    double F_lung1 = 0, F_lung11 = 0, F_lung2 = 0, F_lung3 = 0, F_lung4 = 0, F_lung5 = 0, F_barix = 0, F_bariy = 0, F_bariangle = 0, F_bariangle_template = 0;
                    int DeF_barix = 0, DeF_bariy = 0, DeF_bariangle = 0, DeF_bariangle_template = 0;
                    int X_mezzo_rect_risc = 0, Y_mezzo_rect_risc = 0, X_mezzo_rect_risc1 = 0, Y_mezzo_rect_risc1 = 0;
                    int X_mezzo_rect_risc_pt2 = 0, Y_mezzo_rect_risc_pt2 = 0, X_mezzo_rect_risc_pt3 = 0, Y_mezzo_rect_risc_pt3 = 0;
                    int DeF_Major_Side1 = 0, DeF_Major_Side2 = 0, DeF_Get_Upper_Half_Square = 0, DeF_Get_Lower_Half_Square = 0;
                    
                    cv::Point F_centrale = cv::Point(0 ,0); <------------------------------------------------------- /****** and use these variable into calculation and as result too... so i put it into return struc as you see****/
                    
                    cv::Point F_mezzo_rect_risc = cv::Point(0 ,0);
                    cv::Point F_mezzo_rect_risc1 = cv::Point(0 ,0);
                    cv::Point F_mezzo_rect_risc_pt2 = cv::Point(0 ,0);
                    

                    Regards
                    giorgio

                    gfxxG Offline
                    gfxxG Offline
                    gfxx
                    wrote on last edited by
                    #16

                    @gfxx so I try to define F_centrale into struc func..

                    FindACPTarghet FindCentPoint( cv::Point2f Square_Points[4], bool Find_Upper_Half_Square, bool Find_Lower_Half_Square)
                    {
                    
                        FindACPTarghet FindTarghet;  <----------------------------------------
                    
                       int F_intbarix = 0, F_intbariy = 0;
                        double F_lung1 = 0, F_lung11 = 0, F_lung2 = 0, F_lung3 = 0, F_lung4 = 0, F_lung5 = 0, F_barix = 0, F_bariy = 0, F_bariangle = 0, F_bariangle_template = 0;
                        int DeF_barix = 0, DeF_bariy = 0, DeF_bariangle = 0, DeF_bariangle_template = 0;
                        int X_mezzo_rect_risc = 0, Y_mezzo_rect_risc = 0, X_mezzo_rect_risc1 = 0, Y_mezzo_rect_risc1 = 0;
                        int X_mezzo_rect_risc_pt2 = 0, Y_mezzo_rect_risc_pt2 = 0, X_mezzo_rect_risc_pt3 = 0, Y_mezzo_rect_risc_pt3 = 0;
                        int DeF_Major_Side1 = 0, DeF_Major_Side2 = 0, DeF_Get_Upper_Half_Square = 0, DeF_Get_Lower_Half_Square = 0;
                    
                        cv::Point F_centrale = cv::Point(0 ,0);
                    
                        cv::Point F_mezzo_rect_risc = cv::Point(0 ,0);
                        cv::Point F_mezzo_rect_risc1 = cv::Point(0 ,0);
                        cv::Point F_mezzo_rect_risc_pt2 = cv::Point(0 ,0);
                        cv::Point F_mezzo_rect_risc_pt3 = cv::Point(0 ,0);
                        cv::Point F_un_quarto_rect_risc = cv::Point(0 ,0);
                        cv::Point F_un_quarto_rect_risc1 = cv::Point(0 ,0);
                        cv::Point F_un_quarto_rect_risc_pt2 = cv::Point(0 ,0);
                        cv::Point F_un_quarto_rect_risc_pt3 = cv::Point(0 ,0);
                        bool choose0 = false, choose1 = false, choose2 = false, choose3 = false;
                    
                        F_lung1 = std::pow((std::pow((Square_Points[0].x - Square_Points[1].x),2) + std::pow((Square_Points[0].y - Square_Points[1].y),2)), 0.5);
                        F_lung2 = std::pow((std::pow((Square_Points[1].x - Square_Points[2].x),2) + std::pow((Square_Points[1].y - Square_Points[2].y),2)), 0.5);
                    
                        if (F_lung2 > F_lung1)
                        {..................
                    

                    but result is the same...

                    Regards
                    giorgio

                    bkt

                    gfxxG 1 Reply Last reply
                    0
                    • gfxxG gfxx

                      @gfxx so I try to define F_centrale into struc func..

                      FindACPTarghet FindCentPoint( cv::Point2f Square_Points[4], bool Find_Upper_Half_Square, bool Find_Lower_Half_Square)
                      {
                      
                          FindACPTarghet FindTarghet;  <----------------------------------------
                      
                         int F_intbarix = 0, F_intbariy = 0;
                          double F_lung1 = 0, F_lung11 = 0, F_lung2 = 0, F_lung3 = 0, F_lung4 = 0, F_lung5 = 0, F_barix = 0, F_bariy = 0, F_bariangle = 0, F_bariangle_template = 0;
                          int DeF_barix = 0, DeF_bariy = 0, DeF_bariangle = 0, DeF_bariangle_template = 0;
                          int X_mezzo_rect_risc = 0, Y_mezzo_rect_risc = 0, X_mezzo_rect_risc1 = 0, Y_mezzo_rect_risc1 = 0;
                          int X_mezzo_rect_risc_pt2 = 0, Y_mezzo_rect_risc_pt2 = 0, X_mezzo_rect_risc_pt3 = 0, Y_mezzo_rect_risc_pt3 = 0;
                          int DeF_Major_Side1 = 0, DeF_Major_Side2 = 0, DeF_Get_Upper_Half_Square = 0, DeF_Get_Lower_Half_Square = 0;
                      
                          cv::Point F_centrale = cv::Point(0 ,0);
                      
                          cv::Point F_mezzo_rect_risc = cv::Point(0 ,0);
                          cv::Point F_mezzo_rect_risc1 = cv::Point(0 ,0);
                          cv::Point F_mezzo_rect_risc_pt2 = cv::Point(0 ,0);
                          cv::Point F_mezzo_rect_risc_pt3 = cv::Point(0 ,0);
                          cv::Point F_un_quarto_rect_risc = cv::Point(0 ,0);
                          cv::Point F_un_quarto_rect_risc1 = cv::Point(0 ,0);
                          cv::Point F_un_quarto_rect_risc_pt2 = cv::Point(0 ,0);
                          cv::Point F_un_quarto_rect_risc_pt3 = cv::Point(0 ,0);
                          bool choose0 = false, choose1 = false, choose2 = false, choose3 = false;
                      
                          F_lung1 = std::pow((std::pow((Square_Points[0].x - Square_Points[1].x),2) + std::pow((Square_Points[0].y - Square_Points[1].y),2)), 0.5);
                          F_lung2 = std::pow((std::pow((Square_Points[1].x - Square_Points[2].x),2) + std::pow((Square_Points[1].y - Square_Points[2].y),2)), 0.5);
                      
                          if (F_lung2 > F_lung1)
                          {..................
                      

                      but result is the same...

                      Regards
                      giorgio

                      gfxxG Offline
                      gfxxG Offline
                      gfxx
                      wrote on last edited by
                      #17

                      @gfxx Ok the function works whithout error ... but I have 0 result value for all variables ....

                      Regards
                      giorgio

                      bkt

                      gfxxG 1 Reply Last reply
                      0
                      • gfxxG gfxx

                        @gfxx Ok the function works whithout error ... but I have 0 result value for all variables ....

                        Regards
                        giorgio

                        gfxxG Offline
                        gfxxG Offline
                        gfxx
                        wrote on last edited by
                        #18

                        @gfxx mmm.... these type of approach is not desirable in my case ... so at the last I solve my problem wit a specific c++ class with function that return struct result ... if someone had this same problem or wish to create a class with a return statement struct or a void with a return struct placed here the basic steps ....

                        /*************************FILE.h*********************************/
                        
                        #ifndef FILE_H
                        #define FILE_H
                        
                        #include <QThread> /**** and other magic include ****/
                        #include <QtCore/QVariant>
                        .....
                        
                        
                        struct myFirstStruct{
                            cv::Point2f Square_Points[4];
                            bool Up1_2Square;
                            bool Down1_2Square;
                            bool returnValue1;
                            bool returnValue2;
                            ...... /***other member DECLARE ***/
                        
                        };
                        
                        
                        
                        class File
                        {
                        public:
                            File();
                        
                            myFirstStruct myVoid( cv::Point2f Square_Points[4], bool Up1_2Square, bool Down1_2Square);
                            struct myFirstStruct MyIstance;
                        
                        private:
                        
                        
                        };
                        
                        #endif // FILE_H
                        
                        /*************************FILE.cpp*********************************/
                        
                        #include "File.h"
                        
                        
                        
                        File::File()
                        {
                        
                        }
                        
                        
                          myFirstStruct File::myVoid(cv::Point2f Square_Points[4], bool Up1_2Square, bool Down1_2Square)
                            {
                        /***do somethings*****/
                        
                        MyIstance.returnValue1 = calculatedvalue1;
                        MyIstance.returnValue2 = calculatedvalue2;
                        
                        return MyIstance;
                        }
                        
                        /*************************InSomeFileOfYourApp.cpp*********************************/
                        
                        #include "File.h"
                        
                        int var1; .....
                        
                        Your::mainOrSub(){
                        
                        File MyClassIstance;
                        
                        MyClassIstance.myVoid(cv-point-value, bool-value, bool-value);
                        
                        yourCalculatedData1 =  myVoid.MyIstance.returnValue1;
                        yourCalculatedData2 =  myVoid.MyIstance.returnValue2;
                        
                        .......
                        }
                        
                        
                        
                        

                        I hope These Help someone ...
                        Regards
                        Giorgio

                        bkt

                        VRoninV 1 Reply Last reply
                        -1
                        • gfxxG gfxx

                          @gfxx mmm.... these type of approach is not desirable in my case ... so at the last I solve my problem wit a specific c++ class with function that return struct result ... if someone had this same problem or wish to create a class with a return statement struct or a void with a return struct placed here the basic steps ....

                          /*************************FILE.h*********************************/
                          
                          #ifndef FILE_H
                          #define FILE_H
                          
                          #include <QThread> /**** and other magic include ****/
                          #include <QtCore/QVariant>
                          .....
                          
                          
                          struct myFirstStruct{
                              cv::Point2f Square_Points[4];
                              bool Up1_2Square;
                              bool Down1_2Square;
                              bool returnValue1;
                              bool returnValue2;
                              ...... /***other member DECLARE ***/
                          
                          };
                          
                          
                          
                          class File
                          {
                          public:
                              File();
                          
                              myFirstStruct myVoid( cv::Point2f Square_Points[4], bool Up1_2Square, bool Down1_2Square);
                              struct myFirstStruct MyIstance;
                          
                          private:
                          
                          
                          };
                          
                          #endif // FILE_H
                          
                          /*************************FILE.cpp*********************************/
                          
                          #include "File.h"
                          
                          
                          
                          File::File()
                          {
                          
                          }
                          
                          
                            myFirstStruct File::myVoid(cv::Point2f Square_Points[4], bool Up1_2Square, bool Down1_2Square)
                              {
                          /***do somethings*****/
                          
                          MyIstance.returnValue1 = calculatedvalue1;
                          MyIstance.returnValue2 = calculatedvalue2;
                          
                          return MyIstance;
                          }
                          
                          /*************************InSomeFileOfYourApp.cpp*********************************/
                          
                          #include "File.h"
                          
                          int var1; .....
                          
                          Your::mainOrSub(){
                          
                          File MyClassIstance;
                          
                          MyClassIstance.myVoid(cv-point-value, bool-value, bool-value);
                          
                          yourCalculatedData1 =  myVoid.MyIstance.returnValue1;
                          yourCalculatedData2 =  myVoid.MyIstance.returnValue2;
                          
                          .......
                          }
                          
                          
                          
                          

                          I hope These Help someone ...
                          Regards
                          Giorgio

                          VRoninV Offline
                          VRoninV Offline
                          VRonin
                          wrote on last edited by
                          #19

                          @gfxx Class and Struct are the same thing.

                          struct MyClass{
                          // stuff
                          };
                          // is the same as:
                          class MyClass{
                          public:
                          // stuff
                          };
                          

                          see http://www.cplusplus.com/doc/tutorial/classes/ for a quick overview of how to use classes and structs

                          "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                          ~Napoleon Bonaparte

                          On a crusade to banish setIndexWidget() from the holy land of Qt

                          gfxxG 1 Reply Last reply
                          2
                          • VRoninV VRonin

                            @gfxx Class and Struct are the same thing.

                            struct MyClass{
                            // stuff
                            };
                            // is the same as:
                            class MyClass{
                            public:
                            // stuff
                            };
                            

                            see http://www.cplusplus.com/doc/tutorial/classes/ for a quick overview of how to use classes and structs

                            gfxxG Offline
                            gfxxG Offline
                            gfxx
                            wrote on last edited by
                            #20

                            @VRonin yes struct and class is quite similar .... but not the same things..... I know .. some C programmers not like class and prefer struct .... When I was A good programmer I use me too only struct and no class .... but for now I'm happy class exist .... ;)

                            regards
                            Giorgio

                            bkt

                            VRoninV 1 Reply Last reply
                            0
                            • gfxxG gfxx

                              @VRonin yes struct and class is quite similar .... but not the same things..... I know .. some C programmers not like class and prefer struct .... When I was A good programmer I use me too only struct and no class .... but for now I'm happy class exist .... ;)

                              regards
                              Giorgio

                              VRoninV Offline
                              VRoninV Offline
                              VRonin
                              wrote on last edited by VRonin
                              #21

                              @gfxx C has no classes. C has only structs and they cannot contain methods, just members. C is not an object oriented language. In C++ they are the same, the only difference is the default access level (public for struct, private for class)

                              http://www.geeksforgeeks.org/g-fact-76/

                              "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                              ~Napoleon Bonaparte

                              On a crusade to banish setIndexWidget() from the holy land of Qt

                              gfxxG 1 Reply Last reply
                              2
                              • VRoninV VRonin

                                @gfxx C has no classes. C has only structs and they cannot contain methods, just members. C is not an object oriented language. In C++ they are the same, the only difference is the default access level (public for struct, private for class)

                                http://www.geeksforgeeks.org/g-fact-76/

                                gfxxG Offline
                                gfxxG Offline
                                gfxx
                                wrote on last edited by gfxx
                                #22

                                @VRonin I Know that C has no classes .. I use it sometime, but I study it only 10 year ago and not use it for long long time ...... but I also know that many good programmers using C ++ but most use C do not really like the classes especially if you can use the struct .... but unfortunately I'm not a good programmer ... so use the classes and I facilitate my work .... anyway thanks to this link so today I can learn something new. :))

                                anyhow I'm not a good programmer and if you would suggest me some modification to my code example, in order to make me able to use struct instead class I'm happy to receive your suggest.

                                Some post ago I write these snip:

                                /***********MYQThread .h*****************/
                                
                                struct FindACPTarghet{
                                    cv::Point2f Square_Points[4];
                                    bool Find_Upper_Half_Square;
                                    bool Find_Lower_Half_Square;
                                    cv::Point Get_centrale;
                                    cv::Point Get_mezzo_rect_risc;
                                    cv::Point Get_mezzo_rect_risc1;
                                    cv::Point Get_mezzo_rect_risc_pt2;
                                    cv::Point Get_mezzo_rect_risc_pt3;
                                    double X_Point;
                                    double Y_point;
                                    double Angle;
                                    bool Major_Side1;
                                    bool Major_Side2;
                                    bool Get_Upper_Half_Square;
                                    bool Get_Lower_Half_Square;
                                    //Get_Angle_Central_Point_Targhet GetDataTarghet;
                                }/*FindCentPoint*/;
                                
                                class datathread : public QThread
                                {
                                        Q_OBJECT
                                public:
                                    explicit datathread(QObject *parent = 0, bool bthw = false);
                                    void run();
                                    bool Stop;
                                
                                    FindACPTarghet FindCentPoint( cv::Point2f Square_Points[4], bool Find_Upper_Half_Square, bool Find_Lower_Half_Square);
                                
                                /***********MYQThread .cpp*****************/
                                
                                FindACPTarghet FindCentPoint( cv::Point2f Square_Points[4], bool Find_Upper_Half_Square, bool Find_Lower_Half_Square)
                                {
                                
                                    FindACPTarghet FindTarghet;  <----------------------------------------
                                
                                    F_lung1 = 0;
                                    F_lung2 = 0;
                                    F_lung3 = 0;
                                    F_lung4 = 0;
                                    F_lung5 = 0;
                                    F_barix = 0;
                                    F_bariy = 0;
                                    F_intbarix = 0;
                                    F_intbariy = 0;
                                    F_bariangle = 0;
                                    bool choose0 = false, choose1 = false, choose2 = false, choose3 = false;
                                
                                    F_lung1 = std::pow((std::pow((Square_Points[0].x - Square_Points[1].x),2) + std::pow((Square_Points[0].y - Square_Points[1].y),2)), 0.5);
                                    F_lung2 = std::pow((std::pow((Square_Points[1].x - Square_Points[2].x),2) + std::pow((Square_Points[1].y - Square_Points[2].y),2)), 0.5);
                                
                                    if (F_lung2 > F_lung1)
                                    {..................
                                ........................
                                
                                    FindTarghet.Get_centrale = F_centrale;  <--------------------------------- /*******************************undefined error reference**********************/
                                    FindTarghet.Get_mezzo_rect_risc = F_mezzo_rect_risc;
                                    FindTarghet.Get_mezzo_rect_risc1 = F_mezzo_rect_risc1;
                                    FindTarghet.Get_mezzo_rect_risc_pt2 = F_mezzo_rect_risc_pt2;
                                    FindTarghet.Get_mezzo_rect_risc_pt3 = F_mezzo_rect_risc_pt3;
                                    FindTarghet.X_Point = F_intbarix;
                                    FindTarghet.Y_point = F_intbariy;
                                    FindTarghet.Angle = F_bariangle_template;
                                    FindTarghet.Major_Side1 = false;
                                    FindTarghet.Major_Side2 = false;
                                    FindTarghet.Get_Upper_Half_Square  = false;
                                    FindTarghet.Get_Lower_Half_Square = false;
                                
                                    return FindTarghet;
                                
                                }
                                
                                /***********MYQThread .cpp    qthread::run*****************/
                                void datathread::run()   
                                {
                                ...
                                ...
                                ...
                                
                                FindACPTarghet OneTarghet = FindCentPoint(rect_points, true, false);
                                                                  centrale =  OneTarghet.Get_centrale;
                                                                  mezzo_rect_risc = OneTarghet.Get_mezzo_rect_risc;
                                                                  mezzo_rect_risc1 = OneTarghet.Get_mezzo_rect_risc1;
                                                                  mezzo_rect_risc_pt2 = OneTarghet.Get_mezzo_rect_risc_pt2;
                                                                  mezzo_rect_risc_pt3 = OneTarghet.Get_mezzo_rect_risc_pt3;
                                                                  intbarix = OneTarghet.X_Point;
                                                                  intbariy = OneTarghet.Y_point;
                                                                  bariangle = OneTarghet.Angle;
                                

                                Not work ... but compile is ok...

                                Thank a lot
                                Giorgio

                                bkt

                                1 Reply Last reply
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