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Converting Qbyte array to array and to double

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  • D Offline
    D Offline
    dziko147
    wrote on last edited by
    #5

    @artwaw yes in my code I have

    qDebug()  << "this is data"<< myDatadouble;
    QString DatatoString =QString::number(myDatadouble);
    

    just when i copying it i I was mistaken .

    I update my topic :)

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    • D dziko147

      Hello , I get some data from a CAN Bus . So my data is some float and some double .

      What I did is :

      float myData;
      double myDatadouble;
      
                         QDataStream stream(data);
                          qDebug() << data.size() << " Data Data&size" ;
                         
                          if (data.size()== 5){
                             quint8 byte;
                              stream >> byte; // skip first byte
                    stream.setFloatingPointPrecision(QDataStream::SinglePrecision);
                              stream >> myData; // read data
                              qDebug()  << "this is data"<< myData ;
                              QString DatatoString =QString::number(myData);
                              Outputs[i]=DatatoString;
                          qDebug() << "In outputs data" << Outputs[i];
                          }
      else {
      
                         quint8 byte;
                          stream >> byte; // skip first byte
                              stream.setFloatingPointPrecision(QDataStream::DoublePrecision);
                           stream >> myDatadouble; // read data
                          qDebug()  << "this is data"<< myDatadouble;
                          QString DatatoString =QString::number(myDatadouble);
                          Outputs[i]=DatatoString;
                          qDebug() << "In outputs data" << Outputs[i];
                          }              
                         
      
      

      I get only float converted , the double is usually "0" .

      thankyou

      CP71C Offline
      CP71C Offline
      CP71
      wrote on last edited by CP71
      #6

      @dziko147
      Hi,
      you have checked only if (data.size()== 5) in first if,
      Did you check in else that the data size is correct?
      I think no

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      • D Offline
        D Offline
        dziko147
        wrote on last edited by
        #7

        @CP71 yes it return a size :8 byte

        CP71C 1 Reply Last reply
        0
        • D dziko147

          @CP71 yes it return a size :8 byte

          CP71C Offline
          CP71C Offline
          CP71
          wrote on last edited by
          #8

          @dziko147
          8! so doesn't you have a one spare byte in else as in float case?

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          • D Offline
            D Offline
            dziko147
            wrote on last edited by dziko147
            #9

            @CP71 said in Converting Qbyte array to array and to double:

            8! so doesn't you have a one spare byte in else as in float case?

            no I usually get frame started with FF .

            I mean than in the case of a float I get "FF + 4Byte data"

            In the case of a Double I get "FF +7Byte data "

            and here I skip the first byte

                               quint8 byte;
                                stream >> byte; // skip first byte
            
            CP71C 1 Reply Last reply
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            • D dziko147

              @CP71 said in Converting Qbyte array to array and to double:

              8! so doesn't you have a one spare byte in else as in float case?

              no I usually get frame started with FF .

              I mean than in the case of a float I get "FF + 4Byte data"

              In the case of a Double I get "FF +7Byte data "

              and here I skip the first byte

                                 quint8 byte;
                                  stream >> byte; // skip first byte
              
              CP71C Offline
              CP71C Offline
              CP71
              wrote on last edited by CP71
              #10

              @dziko147 said in Converting Qbyte array to array and to double:

              In the case of a Double I get "FF +7Byte data "

              Sorry, but in double case I think you'd send 0xFF+8bytes, anyway I think your application tries read a double at 8 bytes

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              • D Offline
                D Offline
                dziko147
                wrote on last edited by
                #11

                @CP71 you are right :D

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                • D Offline
                  D Offline
                  dziko147
                  wrote on last edited by
                  #12

                  @CP71 now how can make it readable .
                  For example I get " 3.13891e-43 " for a array "0xff000000e0" .
                  please

                  CP71C 1 Reply Last reply
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                  • D dziko147

                    @CP71 now how can make it readable .
                    For example I get " 3.13891e-43 " for a array "0xff000000e0" .
                    please

                    CP71C Offline
                    CP71C Offline
                    CP71
                    wrote on last edited by
                    #13

                    @dziko147
                    It is wrong!

                    https://www.binaryconvert.com/convert_double.html

                    As last time, I must go.
                    Sorry, bye

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                    • D Offline
                      D Offline
                      dziko147
                      wrote on last edited by
                      #14

                      @CP71 as u like bro good bye

                      1 Reply Last reply
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