Question

The only thing that passed to my mind was, MULT((3+2)(5*4))= 100 not 62? Can someone explain this?

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#define ADD(x1, y1) x1 + y1
#define MULT(x1,y1) x1 * y1


int _tmain(int argc, _TCHAR* argv[])
{
    int a,b,c,d,e,f,g;
    a=2;
    b=3;
    c=4;
    d=5;
    e= MULT(ADD(a,b),MULT(c,d));
    printf("the value of e is: %d\n", e);
    system("PAUSE");
}

Answer 1

When the macros are expanded, this:

MULT(ADD(a,b),MULT(c,d))

becomes:

a + b * c * d

which, replacing the variables with their values, is equivalent to:

2 + 3 * 4 * 5

and the value of this expression, evaluated according to the precedence rules, is 62, because multiplication has higher precedence than addition.

Don’t use macros for this purpose: use functions.