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Error unknown typ name 'DS18B20'

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  • mrjjM mrjj

    @AlexKrammer said in Error unknown typ name 'DS18B20':

    But the one thing that i dont understand yet is. If i create a object each class in CheckTemp and try to call the variables out of them. why they dont include the values which i gave them e.g when the slider moved.

    Because they are NOT tied to the S/R in main. its own variables and unless you
    directly write to them via C.s then they stay at zero.

    So when you change C/S that lives in main, the ones in C does not change with them
    They are seperate variables and has own values and will only change if you directly do that.

    much like

    int NUM =4;

    class Test {
    int NUM=0;
    }

    TEST c;

    NUM = 100;

    will have not change c.NUM at all.

    A Offline
    A Offline
    AlexKrammer
    wrote on last edited by AlexKrammer
    #79

    @mrjj
    yeah but i dont write NUM = 100.
    I write c.NUM = 100.

    i write:

    class TEST{
        int NUM = 0;
    }
    
    MainWindow{
    TEST c;
    c.NUM = 100;
    }
    
    CheckTemperature
    {
         float example;
         TEST c;
         example  = c.NUM;
         //example still 0
    }
    
    
    
    mrjjM 1 Reply Last reply
    0
    • A AlexKrammer

      @mrjj
      yeah but i dont write NUM = 100.
      I write c.NUM = 100.

      i write:

      class TEST{
          int NUM = 0;
      }
      
      MainWindow{
      TEST c;
      c.NUM = 100;
      }
      
      CheckTemperature
      {
           float example;
           TEST c;
           example  = c.NUM;
           //example still 0
      }
      
      
      
      mrjjM Offline
      mrjjM Offline
      mrjj
      Lifetime Qt Champion
      wrote on last edited by
      #80

      @AlexKrammer
      Yes and then its ok. then you update c.num but NOT
      the NUM outside.
      Its 100% the same with your SetTemperature/ReadTemperature
      in MainWin and those in C.

      A 1 Reply Last reply
      0
      • mrjjM mrjj

        @AlexKrammer
        Yes and then its ok. then you update c.num but NOT
        the NUM outside.
        Its 100% the same with your SetTemperature/ReadTemperature
        in MainWin and those in C.

        A Offline
        A Offline
        AlexKrammer
        wrote on last edited by
        #81

        @mrjj
        i dont want to update NUM outside..
        look one post above. I edited it

        mrjjM 1 Reply Last reply
        0
        • A AlexKrammer

          @mrjj
          i dont want to update NUM outside..
          look one post above. I edited it

          mrjjM Offline
          mrjjM Offline
          mrjj
          Lifetime Qt Champion
          wrote on last edited by
          #82

          @AlexKrammer

          CheckTemperature
          {
               float example;
               TEST c;
               example  = c.NUM;
               //example still 0
          }
          

          Yes as you make a local TEST c variable
          so if you did if you did c.NUM=100
          somewhere else its not the same TEST instance.

          So TEST c; should be a member if you want to set its NUM outside of CheckTemperature

          then it works.

          A 1 Reply Last reply
          2
          • mrjjM mrjj

            @AlexKrammer

            CheckTemperature
            {
                 float example;
                 TEST c;
                 example  = c.NUM;
                 //example still 0
            }
            

            Yes as you make a local TEST c variable
            so if you did if you did c.NUM=100
            somewhere else its not the same TEST instance.

            So TEST c; should be a member if you want to set its NUM outside of CheckTemperature

            then it works.

            A Offline
            A Offline
            AlexKrammer
            wrote on last edited by
            #83

            @mrjj
            yes i did it?
            i created a object of Test in MainWindow
            then i put c.NUM = 100;

            after that i created a object of Test in CheckTemperature too
            but c.NUM dont have 100. Its still have 0.

            jsulmJ 1 Reply Last reply
            0
            • A AlexKrammer

              @mrjj
              yes i did it?
              i created a object of Test in MainWindow
              then i put c.NUM = 100;

              after that i created a object of Test in CheckTemperature too
              but c.NUM dont have 100. Its still have 0.

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by
              #84

              @AlexKrammer So, you create two instances of Test, change one of them and expect the other one to have the same change? How? By magic? Maybe I don't get something as the thread is already quite long...

              Test a;
              Test b;
              a.NUM = 100;
              // Why should b.NUM be 100 now?!
              

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

              A 1 Reply Last reply
              1
              • jsulmJ jsulm

                @AlexKrammer So, you create two instances of Test, change one of them and expect the other one to have the same change? How? By magic? Maybe I don't get something as the thread is already quite long...

                Test a;
                Test b;
                a.NUM = 100;
                // Why should b.NUM be 100 now?!
                
                A Offline
                A Offline
                AlexKrammer
                wrote on last edited by AlexKrammer
                #85

                @jsulm
                where do i create two instaces of Test? I only create a Object of TEST with c. change the Variable NUM and try to get c.NUM in a other Class

                class TEST{
                int NUM = 0;
                }

                MainWindow{
                TEST c;
                c.NUM = 100;
                }

                CheckTemperature
                {
                float example;
                TEST c;
                example = c.NUM;
                //example still 0
                }

                Or do i change the value of the variable in the object TEST c (c.NUM) i created? Not the Variable in the class TEST

                jsulmJ 1 Reply Last reply
                0
                • A AlexKrammer

                  @jsulm
                  where do i create two instaces of Test? I only create a Object of TEST with c. change the Variable NUM and try to get c.NUM in a other Class

                  class TEST{
                  int NUM = 0;
                  }

                  MainWindow{
                  TEST c;
                  c.NUM = 100;
                  }

                  CheckTemperature
                  {
                  float example;
                  TEST c;
                  example = c.NUM;
                  //example still 0
                  }

                  Or do i change the value of the variable in the object TEST c (c.NUM) i created? Not the Variable in the class TEST

                  jsulmJ Offline
                  jsulmJ Offline
                  jsulm
                  Lifetime Qt Champion
                  wrote on last edited by jsulm
                  #86

                  @AlexKrammer said in Error unknown typ name 'DS18B20':

                  where do i create two instaces of Test?

                  In the code you just posted (hint: instance is the same thing as object):

                  MainWindow{
                  TEST c; // First instance
                  c.NUM = 100;
                  }
                  
                  CheckTemperature
                  {
                  float example;
                  TEST c; // Second instance, c here is NOT the same as in MainWindow!
                  example = c.NUM;
                  //example still 0
                  }
                  

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

                  mrjjM 1 Reply Last reply
                  2
                  • jsulmJ jsulm

                    @AlexKrammer said in Error unknown typ name 'DS18B20':

                    where do i create two instaces of Test?

                    In the code you just posted (hint: instance is the same thing as object):

                    MainWindow{
                    TEST c; // First instance
                    c.NUM = 100;
                    }
                    
                    CheckTemperature
                    {
                    float example;
                    TEST c; // Second instance, c here is NOT the same as in MainWindow!
                    example = c.NUM;
                    //example still 0
                    }
                    
                    mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by
                    #87

                    @jsulm said in Error unknown typ name 'DS18B20':

                    TEST c; // First instance

                    This has to go in .h , in the MainWindow class and then

                    TEST c; // Second instance, has to be removed then
                    its the same and it should work.

                    A 1 Reply Last reply
                    1
                    • mrjjM mrjj

                      @jsulm said in Error unknown typ name 'DS18B20':

                      TEST c; // First instance

                      This has to go in .h , in the MainWindow class and then

                      TEST c; // Second instance, has to be removed then
                      its the same and it should work.

                      A Offline
                      A Offline
                      AlexKrammer
                      wrote on last edited by
                      #88

                      @mrjj
                      If i create in MainWindow.h a instance called TEST c;

                      That instance won't work in class CheckTemperature. Will it?

                      mrjjM 1 Reply Last reply
                      0
                      • A AlexKrammer

                        @mrjj
                        If i create in MainWindow.h a instance called TEST c;

                        That instance won't work in class CheckTemperature. Will it?

                        mrjjM Offline
                        mrjjM Offline
                        mrjj
                        Lifetime Qt Champion
                        wrote on last edited by
                        #89

                        @AlexKrammer
                        No as its 2 different instances. one in MainWin and one in CheckTemperature.
                        They are not the same.

                        A 1 Reply Last reply
                        0
                        • mrjjM mrjj

                          @AlexKrammer
                          No as its 2 different instances. one in MainWin and one in CheckTemperature.
                          They are not the same.

                          A Offline
                          A Offline
                          AlexKrammer
                          wrote on last edited by
                          #90

                          @mrjj
                          And is there a posibility to use a variable of a class in 2 other classes

                          mrjjM 1 Reply Last reply
                          0
                          • A AlexKrammer

                            @mrjj
                            And is there a posibility to use a variable of a class in 2 other classes

                            mrjjM Offline
                            mrjjM Offline
                            mrjj
                            Lifetime Qt Champion
                            wrote on last edited by
                            #91

                            @AlexKrammer
                            Yes if you use a pointer or reference then it will point back to the original variable.

                            like

                            int Num=0; the actual one

                            class Test() {
                            int &NumRef;
                            void Test( int MyNum ) : NumRef(MyNum) {}
                            }

                            then when you create the instance

                            Test MyTest(Num);

                            Then it points to the actual one and will always have the same value.

                            But often its not the best idea and can be solved other way like give it directly when you want to
                            other classes to use the data.

                            class Test() {
                            int DoSomething(int NumTouse);
                            }

                            Test c;
                            int result = c.DoSomething(Num);

                            A 1 Reply Last reply
                            2
                            • mrjjM mrjj

                              @AlexKrammer
                              Yes if you use a pointer or reference then it will point back to the original variable.

                              like

                              int Num=0; the actual one

                              class Test() {
                              int &NumRef;
                              void Test( int MyNum ) : NumRef(MyNum) {}
                              }

                              then when you create the instance

                              Test MyTest(Num);

                              Then it points to the actual one and will always have the same value.

                              But often its not the best idea and can be solved other way like give it directly when you want to
                              other classes to use the data.

                              class Test() {
                              int DoSomething(int NumTouse);
                              }

                              Test c;
                              int result = c.DoSomething(Num);

                              A Offline
                              A Offline
                              AlexKrammer
                              wrote on last edited by
                              #92

                              @mrjj well thank you very much. My problem has been fixed and about this problem i'm going to read something on a c++ article.
                              Thanks for your time.

                              mrjjM 1 Reply Last reply
                              1
                              • A AlexKrammer

                                @mrjj well thank you very much. My problem has been fixed and about this problem i'm going to read something on a c++ article.
                                Thanks for your time.

                                mrjjM Offline
                                mrjjM Offline
                                mrjj
                                Lifetime Qt Champion
                                wrote on last edited by
                                #93

                                @AlexKrammer
                                Good to hear and you are welcome.
                                Its a good idea to read up on c++ as Qt uses it a lot and
                                its best to have good understanding on some of the concepts as not to feel really uphill:)

                                1 Reply Last reply
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