Funny output on hex value of number

This is a discussion on Funny output on hex value of number within the Windows Programming forums, part of the Platform Specific Boards category; Hi all, I'm trying to output the hex value of 255 to a read only dialog box in MFC. pdu[x]=255 ...

  1. #1
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    Funny output on hex value of number

    Hi all,
    I'm trying to output the hex value of 255 to a read only dialog box in MFC. pdu[x]=255

    sprintf(temp_buffer,"%02x ",pdu[x]);
    output+=temp_buffer;

    Instead of getting ff, I'm getting ffffffff. Any ideas? Thanks
    Shav

  2. #2
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    I might be way off here, but the hex value of the base-10 number 255 is 0xFF. It appears that you are passing the decimal number 255 to the dialog box. I might be reading this wrong though.

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    Yeah, I'm reading in an integer from an edit box. Is there any way to display the number as FF

  4. #4
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    > Instead of getting ff, I'm getting ffffffff. Any ideas? Thanks
    pdu[x] is signed, so it gets sign-extended all the way up to however many bits are in an integer.

    Making your pdu unsigned would do it, as would something like a cast, say
    sprintf( temp_buffer, "%02x ", (unsigned char)pdu[x] );
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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    Brilliant, works a treat!

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