Incrementing styles (x = x++) vs (x +=1) - when to use them

This is a discussion on Incrementing styles (x = x++) vs (x +=1) - when to use them within the C Programming forums, part of the General Programming Boards category; I understand that ++x; is a prefix expression and x++; is a postfix. What I can't grasp the concept of ...

  1. #1
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    Incrementing styles (x = x++) vs (x +=1) - when to use them

    I understand that ++x; is a prefix expression and x++; is a postfix.

    What I can't grasp the concept of is the difference between:

    x = x++; vs. x++;

    Also, while I'm comparison shopping, why use x++; or ++x; as opposed to x = +=1; ?

    If anyone has the time, can you break down the do's and don'ts of:

    x = x++;
    x++;
    x +=1;


    ??

    thanks!
    Last edited by vertigoat; 10-04-2012 at 08:18 AM.

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    Quote Originally Posted by vertigoat
    What I can't grasp the concept of is the difference between:

    x = x++; vs. x++;
    The former results in undefined behaviour; the latter is probably what you wanted to write.

    Quote Originally Posted by vertigoat
    Also, while I'm comparison shopping, why use x++; or ++x; as opposed to x = +=1; ?
    My reasoning is that they are more concise and people are used to them. Otherwise, no big deal. It might even be the case on certain hardware with certain non-optimising compilers that the prefix/postfix operators result in code that is more efficient, but that's generally not a concern.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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    don't: x = x++; (undefined behavior)
    do: x++; or ++x; (either one is valid and acceptable)
    do or don't: x += 1; (valid but not as concise as x++)

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    Thank you! Totally understood now.

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