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Error unknown typ name 'DS18B20'

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  • A AlexKrammer

    @mrjj
    yes it should be possible.
    But to keep the structur and let it look quiet professional i'd tried to put it into a class.
    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.

    mrjjM Offline
    mrjjM Offline
    mrjj
    Lifetime Qt Champion
    wrote on last edited by
    #77

    @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 2 Replies Last reply
    2
    • 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
      #78
      This post is deleted!
      1 Reply Last reply
      0
      • 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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