> Can anybody tell me what output the following program snippet > should produce according to C standard: I think this case produces undefined behavior, so by the C standard, 9 would be as correct as 10 or 42. Compiling your code with "-O2 -Wall" even produces a warning: a.c:5: warning: operation on 'b' may be undefined The reason is that you're modifying a variable twice within the same two sequence points. See http://en.wikipedia.org/wiki/Sequence_point jlh
