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Error unknown typ name 'DS18B20'

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  • 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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