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Cannot pass variable to another Dialog

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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #8

    You are dereferencing your pointer three time, that's why it complains.

    Out of curiosity, what do you have in that three-dimensional table ?

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

    T 1 Reply Last reply
    0
    • M Offline
      M Offline
      mpergand
      wrote on last edited by
      #9

      I think you need a pointer, for example:

      char s[5][2];
      char (*s2)[2]=s;  // pointer to array of two chars
      

      Passing an array to a function is the same as passing a pointer to the first dimension:

      void myFunct(char s[5][2])
      // is the same as:
      void myFunct(char (*s)[2])
      // more simply, you can omit the size of the first dimension:
      void myFunct(char s[][2])
      
      1 Reply Last reply
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      • SGaistS SGaist

        You are dereferencing your pointer three time, that's why it complains.

        Out of curiosity, what do you have in that three-dimensional table ?

        T Offline
        T Offline
        t0msk
        wrote on last edited by t0msk
        #10

        @SGaist said in Cannot pass variable to another Dialog:

        You are dereferencing your pointer three time, that's why it complains.

        Out of curiosity, what do you have in that three-dimensional table ?

        Three-dimensional array represents a 3D space in store.

        My code:

        Store store[5][5][10];
        void MainWindow::setData(Store store_init[][5][10])
        {
            store = store_init;
        }
        
        error: incompatible types in assignment of 'Store (*)[5][10]' to 'Store [5][5][10]'
             store = store_init;
                   ^
        

        Maybe I will set data using three nested loops :D

        Student who loves C/C++

        jsulmJ 1 Reply Last reply
        0
        • T t0msk

          @SGaist said in Cannot pass variable to another Dialog:

          You are dereferencing your pointer three time, that's why it complains.

          Out of curiosity, what do you have in that three-dimensional table ?

          Three-dimensional array represents a 3D space in store.

          My code:

          Store store[5][5][10];
          void MainWindow::setData(Store store_init[][5][10])
          {
              store = store_init;
          }
          
          error: incompatible types in assignment of 'Store (*)[5][10]' to 'Store [5][5][10]'
               store = store_init;
                     ^
          

          Maybe I will set data using three nested loops :D

          jsulmJ Online
          jsulmJ Online
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #11

          @t0msk You cannot do it like this. C/C++ will not copy the content of the array if you assign it to another array. Arrays are basically pointers in C/C++. And [5][5][10] is not the same as [][5][10] (here the first dimension is not specified)!
          You should take a look at std::array.

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

          1 Reply Last reply
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          • T Offline
            T Offline
            t0msk
            wrote on last edited by
            #12

            I dont know how to copy content of whole array to another using 1 line, I solved it by loops:

            int i, j, k;
            
            for(i = 0;i < 5;i++) {
                for(j = 0;j < 5;j++) {
                    for(k = 0;k < 10;k++) {
                        store[i][j][k] = store_init[i][j][k];
                    }
                }
            }
            

            Student who loves C/C++

            jsulmJ 1 Reply Last reply
            0
            • T Offline
              T Offline
              t0msk
              wrote on last edited by
              #13

              One more question.

              Calling window:

              int test = 7;
              
              Dialog *window = new Dialog();
              window->setAttribute(Qt::WA_DeleteOnClose);
              window->setData(test);
              window->show();
              

              Dialog.h

              public:
                  explicit Dialog(QWidget *parent = 0);
                  ~Dialog();
                  void setData(int test);
              

              Dialog.cpp

              int second;
              
              Dialog::Dialog(QWidget *parent) :
                  QDialog(parent),
                  ui(new Ui::Dialog)
              {
                  ui->setupUi(this);
              
                  ui->label->setText(QString::number(second));
              }
              
              void Dialog::setData(int test) {
              
                  second = test;
              }
              
              Dialog::~Dialog()
              {
                  delete ui;
              }
              

              Problem is that value in ui->label is 0 and not 7, why? :/

              Student who loves C/C++

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

                Because it's test that is 7 and second is not initialised so it's pure luck that it's 0.

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

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                • T Offline
                  T Offline
                  t0msk
                  wrote on last edited by
                  #15

                  And how to initialise "second"?

                  Student who loves C/C++

                  1 Reply Last reply
                  0
                  • SGaistS Offline
                    SGaistS Offline
                    SGaist
                    Lifetime Qt Champion
                    wrote on last edited by
                    #16

                    Assign it a value in the constructor initializer list.

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

                    1 Reply Last reply
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                    • M Offline
                      M Offline
                      mpergand
                      wrote on last edited by
                      #17
                      void Dialog::setData(int test) {
                        second = test;
                       ui->label->setText(QString::number(second));
                      }
                      

                      In the constructor, you can set the default value ( 0 ?)

                      1 Reply Last reply
                      0
                      • T t0msk

                        I dont know how to copy content of whole array to another using 1 line, I solved it by loops:

                        int i, j, k;
                        
                        for(i = 0;i < 5;i++) {
                            for(j = 0;j < 5;j++) {
                                for(k = 0;k < 10;k++) {
                                    store[i][j][k] = store_init[i][j][k];
                                }
                            }
                        }
                        
                        jsulmJ Online
                        jsulmJ Online
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by
                        #18

                        @t0msk You could use the C function memcpy() - it is much more efficient compared to your solution and is only one line :-)

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

                        1 Reply Last reply
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