incremental multiplication problem
Hi everyone,
I am a beginner of C and am stuck on a problem like below int i=3, j, k; j = i++*i++; k = ++i*++i; print ("j=%d k=%d", j, k); As per my calculations the values should be j=12 and k=42 but the value of the code turns out to be j=9 and k=49. I don't understand why it happens. Can anyone explain the reason. Thanks for any Help 
Re: incremental multiplication problem
Just play a bit with operators and you will find out how to use to obtain correct result.

Re: incremental multiplication problem

Re: incremental multiplication problem
Quote:
the compiler first evaluates the expression j = i++*i++ and then increments i 2 times in a row and opposite for ++i means there it first increments i 2 times in a row and then evaluates the exp k = ++i*++i Thanks 
Re: incremental multiplication problem
Quote:
It contains some good points. Thanks 
Re: incremental multiplication problem
Quote:
So i=3; j=i++ * i++; could mean j=i(3, post incremented to 4) * i(4, post incremented to 5)=12, OR it could mean j=i*i(post incremented twice to 5)=9. The result is compiler dependent. In Visual Studio j=i++*i++; is equivalent to j=i*i; i++; i++; but you cannot guarantee this for all compilers (or even all versions of Visual Studio). The end result of this is that if you only need a variable once in an expression, it's safe to use modifiers, but if you need it more than once, use it WITHOUT pre/post increment/decrement within the expression, THEN modify it. By the way, this is a very frequently asked question. Check out stuff like the C++ FAQ before asking anything else. It will almost certainly answer your next 20 questions, plus there will be a load of other interesting stuff in there, so it's well worth a read. 
All times are GMT +5.5. The time now is 10:20. 