Different output than expected

[Nirvin M]

Why does the following snippet produces different result than expected?

#include <stdio.h>

int main()
{
    int i = 5;
    printf("%d %d %d", i++, i++, ++i);
    getchar();
}

I compiled and run this code with Visual C++ 2010 and it produces the output

7 6 8

instead of

7 6 6

Why?

[deceptikon]

Why does the following snippet produces different result than expected?

Undefined behavior was invoked. Your expectations are invalid.

http://en.wikipedia.org/wiki/Undefined_behavior

http://c-faq.com/expr/evalorder1.html

http://c-faq.com/expr/ieqiplusplus.html

[TrustyTony]

So you should do something like this:

include <stdio.h>

int main()
{
    int i = 5;
    printf("%d", i++);
    printf("%d", i++);
    printf("%d", ++i);
    getchar();
}

Output:

568

Then you have clear code points for expressions. Not that I would call postincrement and right after preincrement to be good style, better:

#include <stdio.h>

int main()
{
    int i = 5;
    printf("%d", i);
    printf("%d", ++i);
    printf("%d", i+=2);
    getchar();
}