/* some pointer fun and games */

#include<stdio.h>

int main()
{
	int x, y;	/* integer variables */
	int *ptr, *ptry;	/* a pointer to an integer variable */
	
	x = 256;	/* assigning the variable 'x' the value 256 */
	ptr = &x;	/* assigning the address of 'x' in memory to the pointer 'ptr' */

	y = *ptr;	/* ptr is dereferenced to assign the 
			   value 256 to y */

	ptry = &y;
	
	printf("x is %d\n", x); 	/* printing the value of x */
	printf("&x is %u\n", &x);	/* printing the address of x */
	printf("*ptr is %d\n", *ptr);	/* printing what ptr points to */
	printf("ptr is %u\n", ptr);	/* printing the address ptr points to */
	printf("y is %d\n", y);		/* printing the value of y */
	printf("*ptry is %d\n", *ptry);
	printf("ptry is %u\n\n", ptry);

	*ptr = *ptr - 22;	

        printf("x is %d\n", x);         /* printing the value of x */
        printf("&x is %u\n", &x);       /* printing the address of x */
        printf("*ptr is %d\n", *ptr);   /* printing what ptr points to */
        printf("ptr is %u\n", ptr);     /* printing the address ptr points to */
        printf("y is %d\n", y);         /* printing the value of y */  
        printf("*ptry is %d\n", *ptry);
        printf("ptry is %u\n\n", ptry);
 


	*ptr = *ptr - y;	

        printf("x is %d\n", x);         /* printing the value of x */
        printf("&x is %u\n", &x);       /* printing the address of x */
        printf("*ptr is %d\n", *ptr);   /* printing what ptr points to */
        printf("ptr is %u\n", ptr);     /* printing the address ptr points to */
        printf("y is %d\n", y);         /* printing the value of y */  
        printf("*ptry is %d\n", *ptry);
        printf("ptry is %u\n\n", ptry);
 


	*ptr = *ptry + x;

        printf("x is %d\n", x);         /* printing the value of x */
        printf("&x is %u\n", &x);       /* printing the address of x */
        printf("*ptr is %d\n", *ptr);   /* printing what ptr points to */
        printf("ptr is %u\n", ptr);     /* printing the address ptr points to */
        printf("y is %d\n", y);         /* printing the value of y */  
        printf("*ptry is %d\n", *ptry);
        printf("ptry is %u\n\n", ptry);
 

}