K&R(5.2): Pointers and Function Arguments

/* k&r(5.2): pointers and function arguments
   created on Mar 21, 2011
   */
#include    "stdio.h"

void swap1(int, int);
void swap2(int *, int *);

/* main: test pointer as function arguments to swap two ints */
int main()
{
    int i = 3, j = 2, *pi, *pj;
    pi = &i, pj = &j;
    swap1(i, j);
//    swap2(pi, pj);
    printf("i=%d, j=%d\n", i, j);
    return 0;
}

/* wrong version: pass arguments by values */
void swap1(int x, int y)
{
    int temp;
    temp = x;
    x = y;
    y = temp;

}

/* correct version: pass arguments by pointer or address */
void swap2(int *x, int *y)
{
    int temp;
    temp = *x;
    *x = *y;
    *y = temp;

}