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Is there a "new" style for casting?

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  • 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
                                    0
                                    • S saber

                                      @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 Offline
                                      sierdzioS Offline
                                      sierdzio
                                      Moderators
                                      wrote on last edited by
                                      #37

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

                                      @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 .

                                      These are hints from clang on how to improve your code. You are not forced to do everything it says. You are seeing them now because the clang code model is default since Qt Creator 4.7. So previously you were using the old code model which did not offer these hints. That's all there is to it. If the code compiles fine (without warnings), you can ignore the hints.

                                      However, it is a good idea to at least consider them, because these hints are (in 90% of cases) very good hints indeed.

                                      In this case yes, I'd strongly recommend using nullptr rather than zero. It is an explicit, named value that makes it harder to make a mistake.

                                      (Z(:^

                                      S 1 Reply Last reply
                                      4
                                      • VRoninV Offline
                                        VRoninV Offline
                                        VRonin
                                        wrote on last edited by
                                        #38

                                        I'm late to the party but just wanted to note Qt provides qFuzzyCompare and qFuzzyIsNull to compare double numbers for equality but you have to read the docs carefully before using them

                                        "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                                        ~Napoleon Bonaparte

                                        On a crusade to banish setIndexWidget() from the holy land of Qt

                                        1 Reply Last reply
                                        2
                                        • sierdzioS sierdzio

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

                                          @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 .

                                          These are hints from clang on how to improve your code. You are not forced to do everything it says. You are seeing them now because the clang code model is default since Qt Creator 4.7. So previously you were using the old code model which did not offer these hints. That's all there is to it. If the code compiles fine (without warnings), you can ignore the hints.

                                          However, it is a good idea to at least consider them, because these hints are (in 90% of cases) very good hints indeed.

                                          In this case yes, I'd strongly recommend using nullptr rather than zero. It is an explicit, named value that makes it harder to make a mistake.

                                          S Offline
                                          S Offline
                                          saber
                                          wrote on last edited by
                                          #39

                                          @sierdzio
                                          i am adding all the fix that qtcreator suggesting .

                                          as for the " #endif " i am ignoring it.

                                          aha_1980A 1 Reply Last reply
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