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

If you really think it is necessary to use such macros, you'll need to use parenthesis () to avoid side-effects:

#define VAL1(a,b)    ((a)*(b))
#define VAL2(a,b)    ((a)/(b))
#define VAL3(a,b)    ((++a)%(b))