how to put hex numbers into a Qbytearray?

[Nimika]

Hello,
Can anyone suggest me about how to use hex number which are in ASCII form as a Qbytearray?
Actually I am converting my decimal number into hex number which is then stored as its ascii character using this function

QByteArray double2HexString(double n)
{   
   unsigned char hexaDeciNum[20];
   QByteArray hexbyte ;
    int i = 0;
    while(n!=0)
    {   
        int temp  = 0;
        temp = n % 16;
        if(temp < 10)
        {
            hexaDeciNum[i] = temp + 48;
            i++;
        }
        else
        {
            hexaDeciNum[i] = temp + 55;
            i++;
        }
        n = n/16;
    }
      for(int j=i-1; j>=0; j--)
        cout << hexaDeciNum[j];

hexbyte = QByteArray((char*)hexDeciNum,20);
return hexbyte;
}

which then I need to send to another function which is storing the hex number into an array using this function byte by byte.

void writeout_RS5(){
   QByteArray writedata_RS5;
QByteArray value;
     qDebug()<<"helloooooooooo";
    writedata_RS5=double2HexString(data);
    value[0]=  writedata_RS5[0];
    value[1]= writedata_RS5[1];
    qDebug()<<writedata_RS5.toHex();

Where m I wrong?
What can I do now?
Can anyone help?

[Added code tags ~kshegunov]

[jsulm]

@Nimika There is a much much easier way to convert numbers to hex: http://doc.qt.io/qt-5/qstring.html#number

[mostefa]

@jsulm said in how to put hex numbers into a Qbytearray?:

@Nimika There is a much much easier way to convert numbers to hex: http://doc.qt.io/qt-5/qstring.html#number

Or even a QByteArray::number since you want to store the result in a QByteArray

[J.Hilk]

@mostefa if we go that far, QByteArray accepts an int value as constructor:

QByteArray byteArray1(61455);
//or
QByteArray byteArray2(0xF00F);