/* This program demonstrates pointers to various types */
#include <stdio.h>

/*
   Swap the values of the variables pointed to by pa and pb.
   By using pointers parameters, this effectively renders the
   parameter passing "by reference".
*/
void swap(int *pa, int *pb) {
    int temp = *pa;
    *pa = *pb;
    *pb = temp;
}

int main()
{
    int x, y;

    int *pa, n;
    

    x = 1;
    y = 2;
    /* prints original values of x and y */
    printf("x = %d, y = %d\n", x, y);

    swap(&x, &y);

    /* prints current values of x and y after swapping */
    printf("x = %d, y = %d\n", x, y);

    n = 5;
    printf("n = %d\n", n);
    pa = &n;
    /* pa is now pointing to the n, so *pa is equal to n,
       which is 5 in this case */
    printf("*pa = %d\n", *pa);

    /* we now change the value pointed to by pa to 6 */
    *pa = 6;
    printf("*pa = %d\n", *pa);

    /* now the value of n is 6, since pa points to n */
    printf("n = %d\n", n);

    return 0;
}