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Is there a "new" style for casting?

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  • jsulmJ jsulm

    @Abrar said in Is there a "new" style for casting?:

    static_cast<int>(screensize().width() * .8)

    Yes, this is C++ type cast.

    (int)(someVariabl);
    

    Old C style cast which should not be used in C++.
    See https://stackoverflow.com/questions/332030/when-should-static-cast-dynamic-cast-const-cast-and-reinterpret-cast-be-used

    AbrarA Offline
    AbrarA Offline
    Abrar
    wrote on last edited by
    #17

    @jsulm ok now understand the difference.
    Thanks...

    1 Reply Last reply
    0
    • J.HilkJ J.Hilk

      @jsulm
      technically,

      int(someVariabl);

      is a valid "conversion", as it's a functional notation

      jsulmJ Offline
      jsulmJ Offline
      jsulm
      Lifetime Qt Champion
      wrote on last edited by
      #18

      @J.Hilk Both are C-style casts

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

      J.HilkJ sierdzioS 2 Replies Last reply
      0
      • S Offline
        S Offline
        saber
        wrote on last edited by saber
        #19

        guys what a
        @saber = static_cast<learn>( @jsulm and @J-Hilk ; (i think)

        thanks.learned alot.

        AbrarA 1 Reply Last reply
        1
        • S saber

          guys what a
          @saber = static_cast<learn>( @jsulm and @J-Hilk ; (i think)

          thanks.learned alot.

          AbrarA Offline
          AbrarA Offline
          Abrar
          wrote on last edited by
          #20

          @saber you wrote the clever statement ever.
          !!!!

          1 Reply Last reply
          0
          • jsulmJ jsulm

            @J.Hilk Both are C-style casts

            J.HilkJ Offline
            J.HilkJ Offline
            J.Hilk
            Moderators
            wrote on last edited by J.Hilk
            #21

            @jsulm thats not what @aha_1980 said earlier, and what I read from my trusted source
            (http://www.cplusplus.com/doc/tutorial/typecasting/) :-)

            the new (qtcreator)clang code model seems to agree as well, as int(xy) is not flaged as old style casting.


            Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


            Q: What's that?
            A: It's blue light.
            Q: What does it do?
            A: It turns blue.

            jsulmJ 1 Reply Last reply
            1
            • J.HilkJ J.Hilk

              @jsulm thats not what @aha_1980 said earlier, and what I read from my trusted source
              (http://www.cplusplus.com/doc/tutorial/typecasting/) :-)

              the new (qtcreator)clang code model seems to agree as well, as int(xy) is not flaged as old style casting.

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by
              #22

              @J.Hilk Yeah, I think I was wrong on function style cast you mentioned

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

              1 Reply Last reply
              0
              • S Offline
                S Offline
                saber
                wrote on last edited by saber
                #23

                i got more warnings to fix.

                0_1534227012370_t.png

                    switch( m_model->state() ) {
                        case Battery::FullyCharged:
                            ui->statusEdit->setText( tr( "Full Charged" ) );
                            ui->timerLblEdit->setText( tr( "Full Charged" ) );
                            break;
                        case Battery::Discharging:
                            addSeconds = static_cast<int>(m_model->toEmpty());
                            addSeconds = rate != 0 && addSeconds == 0 ? ( energy - energyEmpty ) * 4 / rate: addSeconds;
                            ui->statusEdit->setText( tr( "Discharging" ) );
                            ui->timerLblEdit->setText( tr( "Discharged in : " ) );
                            break;
                        case Battery::Charging:
                            addSeconds = static_cast<int>(m_model->toFull());
                            addSeconds = rate != 0 && addSeconds == 0 ? ( energyFull - energy ) * 4 / rate : addSeconds;
                            ui->statusEdit->setText( tr( "Charging" ) );
                            ui->timerLblEdit->setText( tr( "Charged in : " ) );
                            break;
                        default:
                            ui->statusEdit->setText( tr( "No Battery" ) );
                            ui->timerLblEdit->setText( tr( "No Battery" ) );
                            break;
                    }
                
                jsulmJ 1 Reply Last reply
                0
                • jsulmJ jsulm

                  @J.Hilk Both are C-style casts

                  sierdzioS Offline
                  sierdzioS Offline
                  sierdzio
                  Moderators
                  wrote on last edited by
                  #24

                  @jsulm said in Is there a "new" style for casting?:

                  @J.Hilk Both are C-style casts

                  Yep but clang does not complain about int(something) while it does complain about (int) something. Just sayin' :-)

                  (Z(:^

                  1 Reply Last reply
                  0
                  • S saber

                    i got more warnings to fix.

                    0_1534227012370_t.png

                        switch( m_model->state() ) {
                            case Battery::FullyCharged:
                                ui->statusEdit->setText( tr( "Full Charged" ) );
                                ui->timerLblEdit->setText( tr( "Full Charged" ) );
                                break;
                            case Battery::Discharging:
                                addSeconds = static_cast<int>(m_model->toEmpty());
                                addSeconds = rate != 0 && addSeconds == 0 ? ( energy - energyEmpty ) * 4 / rate: addSeconds;
                                ui->statusEdit->setText( tr( "Discharging" ) );
                                ui->timerLblEdit->setText( tr( "Discharged in : " ) );
                                break;
                            case Battery::Charging:
                                addSeconds = static_cast<int>(m_model->toFull());
                                addSeconds = rate != 0 && addSeconds == 0 ? ( energyFull - energy ) * 4 / rate : addSeconds;
                                ui->statusEdit->setText( tr( "Charging" ) );
                                ui->timerLblEdit->setText( tr( "Charged in : " ) );
                                break;
                            default:
                                ui->statusEdit->setText( tr( "No Battery" ) );
                                ui->timerLblEdit->setText( tr( "No Battery" ) );
                                break;
                        }
                    
                    jsulmJ Offline
                    jsulmJ Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by
                    #25

                    @saber said in Is there a "new" style for casting?:

                    i got more warnings to fix.

                    So, fix them

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

                    S 1 Reply Last reply
                    1
                    • jsulmJ jsulm

                      @saber said in Is there a "new" style for casting?:

                      i got more warnings to fix.

                      So, fix them

                      S Offline
                      S Offline
                      saber
                      wrote on last edited by
                      #26

                      @jsulm
                      sorry .
                      i don't think those are casting.and i am not understanding what is the fix.

                      jsulmJ 1 Reply Last reply
                      0
                      • S saber

                        @jsulm
                        sorry .
                        i don't think those are casting.and i am not understanding what is the fix.

                        jsulmJ Offline
                        jsulmJ Offline
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by jsulm
                        #27

                        @saber The first warning says already what the problem is: comparing floating point numbers with == and != isn't save because of inaccuracy of such numbers represented in a computer. Depending on what you really want you should cast to int or use <, > for comparisions.
                        For the second warning take a look at https://softwareengineering.stackexchange.com/questions/179269/why-does-clang-llvm-warn-me-about-using-default-in-a-switch-statement-where-all
                        In general, you should try to find out what the problem is by yourself first before going to a forum and asking. Or do you want to ask for each and every warning you get? I mean, I'm happy to help, but sometimes I have the impression that people don't even try to find an answer by themselves.

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

                        S 1 Reply Last reply
                        2
                        • jsulmJ jsulm

                          @saber The first warning says already what the problem is: comparing floating point numbers with == and != isn't save because of inaccuracy of such numbers represented in a computer. Depending on what you really want you should cast to int or use <, > for comparisions.
                          For the second warning take a look at https://softwareengineering.stackexchange.com/questions/179269/why-does-clang-llvm-warn-me-about-using-default-in-a-switch-statement-where-all
                          In general, you should try to find out what the problem is by yourself first before going to a forum and asking. Or do you want to ask for each and every warning you get? I mean, I'm happy to help, but sometimes I have the impression that people don't even try to find an answer by themselves.

                          S Offline
                          S Offline
                          saber
                          wrote on last edited by
                          #28

                          @jsulm
                          i understand all the warnings but problem is i don't know how to fix those .

                          i know this issues are small and silly to ask to help.but i have no other way. my app's co-developer is in off-line. i am a ui designer and newbie c++ developer .

                          thanks.

                          jsulmJ 1 Reply Last reply
                          0
                          • S saber

                            @jsulm
                            i understand all the warnings but problem is i don't know how to fix those .

                            i know this issues are small and silly to ask to help.but i have no other way. my app's co-developer is in off-line. i am a ui designer and newbie c++ developer .

                            thanks.

                            jsulmJ Offline
                            jsulmJ Offline
                            jsulm
                            Lifetime Qt Champion
                            wrote on last edited by jsulm
                            #29

                            @saber I already suggested what to change and provided a link. And you can round the floating point numbers to int to get rid of this message. And you can use Google.
                            Also you should think about whether you need floating point numbers at all...

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

                            S 1 Reply Last reply
                            0
                            • jsulmJ jsulm

                              @saber I already suggested what to change and provided a link. And you can round the floating point numbers to int to get rid of this message. And you can use Google.
                              Also you should think about whether you need floating point numbers at all...

                              S Offline
                              S Offline
                              saber
                              wrote on last edited by
                              #30

                              @jsulm
                              yes , it seems fixed.

                                  switch( m_model->state() ) {
                                      case Battery::FullyCharged:
                                          ui->statusEdit->setText( tr( "Full Charged" ) );
                                          ui->timerLblEdit->setText( tr( "Full Charged" ) );
                                          break;
                                      case Battery::Discharging:
                                          addSeconds = static_cast<int>(m_model->toEmpty());
                                          addSeconds = static_cast<int>(rate) != 0 && addSeconds == 0 ? static_cast<int>(( energy - energyEmpty ) * 4 / rate) : addSeconds;
                                          ui->statusEdit->setText( tr( "Discharging" ) );
                                          ui->timerLblEdit->setText( tr( "Discharged in : " ) );
                                          break;
                                      case Battery::Charging:
                                          addSeconds = static_cast<int>(m_model->toFull());
                                          addSeconds = static_cast<int>(rate) != 0 && addSeconds == 0 ? static_cast<int>(( energyFull - energy ) * 4 / rate) : addSeconds;
                                          ui->statusEdit->setText( tr( "Charging" ) );
                                          ui->timerLblEdit->setText( tr( "Charged in : " ) );
                                          break;
                                      default:
                                          ui->statusEdit->setText( tr( "No Battery" ) );
                                          ui->timerLblEdit->setText( tr( "No Battery" ) );
                                          break;
                                  }
                              

                              as for the default , i read the post and understand that i can't do anything as the library i am using there is no eum like "no battery" . so it needs the default case.

                              jsulmJ 1 Reply Last reply
                              0
                              • S saber

                                @jsulm
                                yes , it seems fixed.

                                    switch( m_model->state() ) {
                                        case Battery::FullyCharged:
                                            ui->statusEdit->setText( tr( "Full Charged" ) );
                                            ui->timerLblEdit->setText( tr( "Full Charged" ) );
                                            break;
                                        case Battery::Discharging:
                                            addSeconds = static_cast<int>(m_model->toEmpty());
                                            addSeconds = static_cast<int>(rate) != 0 && addSeconds == 0 ? static_cast<int>(( energy - energyEmpty ) * 4 / rate) : addSeconds;
                                            ui->statusEdit->setText( tr( "Discharging" ) );
                                            ui->timerLblEdit->setText( tr( "Discharged in : " ) );
                                            break;
                                        case Battery::Charging:
                                            addSeconds = static_cast<int>(m_model->toFull());
                                            addSeconds = static_cast<int>(rate) != 0 && addSeconds == 0 ? static_cast<int>(( energyFull - energy ) * 4 / rate) : addSeconds;
                                            ui->statusEdit->setText( tr( "Charging" ) );
                                            ui->timerLblEdit->setText( tr( "Charged in : " ) );
                                            break;
                                        default:
                                            ui->statusEdit->setText( tr( "No Battery" ) );
                                            ui->timerLblEdit->setText( tr( "No Battery" ) );
                                            break;
                                    }
                                

                                as for the default , i read the post and understand that i can't do anything as the library i am using there is no eum like "no battery" . so it needs the default case.

                                jsulmJ Offline
                                jsulmJ Offline
                                jsulm
                                Lifetime Qt Champion
                                wrote on last edited by
                                #31

                                @saber You can: remove the default. If then a new value is added to the enum you will get a warning from compiler that this new value is not handled.

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

                                1 Reply Last reply
                                0
                                • S Offline
                                  S Offline
                                  saber
                                  wrote on last edited by saber
                                  #32

                                  for now i will leave as it is and inform the library author to add that enm.

                                  i got more warning to fix.

                                  0_1534231505882_aw.png

                                  i am getting this in all my ui based header file .
                                  but the app compiles fine.

                                  sierdzioS JonBJ jsulmJ 3 Replies Last reply
                                  0
                                  • S saber

                                    for now i will leave as it is and inform the library author to add that enm.

                                    i got more warning to fix.

                                    0_1534231505882_aw.png

                                    i am getting this in all my ui based header file .
                                    but the app compiles fine.

                                    sierdzioS Offline
                                    sierdzioS Offline
                                    sierdzio
                                    Moderators
                                    wrote on last edited by
                                    #33

                                    @saber said in Is there a "new" style for casting?:

                                    for now i will leave as it is and inform the library author to add that enm.

                                    i got more warning to fix.

                                    0_1534231505882_aw.png

                                    i am getting this in all my ui based header file .
                                    but the app compiles fine.

                                    Ignore it, then. The code model sometimes gets bogged down in ifdefs without reason.

                                    (Z(:^

                                    1 Reply Last reply
                                    0
                                    • S saber

                                      for now i will leave as it is and inform the library author to add that enm.

                                      i got more warning to fix.

                                      0_1534231505882_aw.png

                                      i am getting this in all my ui based header file .
                                      but the app compiles fine.

                                      JonBJ Offline
                                      JonBJ Offline
                                      JonB
                                      wrote on last edited by
                                      #34

                                      @saber
                                      Although we cannot be sure, chances are that the last line of that header file should be:

                                      #endif
                                      

                                      to match the #ifndef started at line #17. (This is a common pattern to allow a header to be included more than once without it doing any harm.) Have a look at other header files (maybe from the same library?) and you should see this. You should fix this by adding the line --- at present the compiler/editor will be treating your file as though it did have that line at the end.

                                      sierdzioS S 2 Replies Last reply
                                      0
                                      • JonBJ JonB

                                        @saber
                                        Although we cannot be sure, chances are that the last line of that header file should be:

                                        #endif
                                        

                                        to match the #ifndef started at line #17. (This is a common pattern to allow a header to be included more than once without it doing any harm.) Have a look at other header files (maybe from the same library?) and you should see this. You should fix this by adding the line --- at present the compiler/editor will be treating your file as though it did have that line at the end.

                                        sierdzioS Offline
                                        sierdzioS Offline
                                        sierdzio
                                        Moderators
                                        wrote on last edited by
                                        #35

                                        @JonB said in Is there a "new" style for casting?:

                                        at present the compiler/editor will be treating your file as though it did have that line at the end.

                                        Whoa, really? Which compiler allows that?

                                        For me (GCC) an unterminated ifdef is a hard error, compiler does not implicitly add it.

                                        (Z(:^

                                        JonBJ 1 Reply Last reply
                                        2
                                        • JonBJ JonB

                                          @saber
                                          Although we cannot be sure, chances are that the last line of that header file should be:

                                          #endif
                                          

                                          to match the #ifndef started at line #17. (This is a common pattern to allow a header to be included more than once without it doing any harm.) Have a look at other header files (maybe from the same library?) and you should see this. You should fix this by adding the line --- at present the compiler/editor will be treating your file as though it did have that line at the end.

                                          S Offline
                                          S Offline
                                          saber
                                          wrote on last edited by
                                          #36

                                          @JonB
                                          on every file "#endif " is added from first .
                                          all the warnings was coming up after the update of qtcreator.

                                          see this
                                          on the old version qt created this by it self

                                          explicit MainWindow(QWidget *parent = 0);
                                          

                                          after update
                                          0_1534232269589_y.png

                                          should i replace the 0 with nullpointer on every file??
                                          should it be a error in older version of compiler??
                                          in my qmake i add that must have c++ 11 support .

                                          sierdzioS 1 Reply Last reply
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