Strange behavior of Macro-expansion

Question

Here\'s the code:

#include 
#include 
#define VAL1(a,b)    a*b
#define VAL2(a,b)    a/b
#define VAL3(a,b)    ++a%b
int main()
{         


        

Answer 1

I tried to compile it with GCC 4.7, and the two expressions gave the same results.

If you want to see how macro will expand, you can use cpp, which is the C Preprossessor, and will give you the output after preprocessor expression are executed, here the output is

int main()
{
    int a = 1;
    int b = 2;
    int c = 3;
    int d = 3;
    int e = 5;

    int result = a/d/e*b+++c%d;  
    int result2 = a/d/e*b+++c%d;  

    printf("%d %d\n", result, result2);

    return 0;
}