Unary operation are sometimes suicidal.Mess up with C code

Question

Code in C language.

#include<stdio.h>
#define PRODUCT(x) ( x * x * x)
int main()
{
  int i =5,k;
  k = PRODUCT( ++i );
  printf("i is :%d ",k);
  return 0;
}

My Question is why i is : 392? According to me output should be 336. (because 6 * 7 * 8 = 336)

Am I really messed up here??

[error with define macro definition](http://stackoverflow.com/questions/17038558/error-with-define-macro-definition/17038596#17038596) — Grijesh Chauhan, Aug 29 '13 at 12:53
@GrijeshChauhan You are Wrong..Please see Dayal rai comment below to see how it will be preprocessed. — Level29Access, Aug 29 '13 at 12:55
@Level29Access my answer is perfectly correct over there, that is quit related to your answer. yes Dayal rai's answer it correct, you can vote & accept the answer — Grijesh Chauhan, Aug 29 '13 at 13:00
@GrijeshChauhan Sorry I haven't visited the link..+1 for correcting me. — Level29Access, Aug 29 '13 at 13:03

score 3 · Accepted Answer · answered Aug 29 '13 at 12:51

3

Preprocessed code will have

( ++i * ++i * ++i)

which have Lack of sequence point between the two execution on same variable resulting Undefined behaviour.

answered Aug 29 '13 at 12:51

Dayal rai

1 Answers1