/*
* A D D _ P T R 
* Demonstrate the declaration and the use of pinters 
*/
int
main(void)
{
    int num1, num2, sum;    /* declare var names */
    int *np1, *np2, *sp;    /* declare pointers to integers */
    /*
     * Load ptrs with addresses of the declared variable
    */

    np1 = &num1;        /* Writes address of num1 in np1 */
    np2 = &num2;        /* Writes address of num2 in np2 */
    sp = ∑        /* writes addres of sum in sp */

    /*
    * Put values into memory locations pointed to by the ptrs
    */

    *np1 = 5;
    *np2 = 7;
    *sp = *np1 + *np2;    /* result is written in mem loc. 
                   pointed to by sp */

    /*
    * Print out the adresses of the vars and their contents
    */

    printf("\nName\t        Address\t      Value\n");
    printf("\n----\t        -------\t      -----\n");
    printf("%s\t%u\t%d\n", "number 1", &num1, *np1);
    printf("%s\t%u\t%d\n", "number 2", &num2, *np2);
    printf("%s\t%u\t%d\n", "sum     ", &sum, *sp);
    printf("%s\t%u\t%d\n", "*np1    ", &np1, np1);
    printf("%s\t%u\t%d\n", "*np2    ", &np2, np2);
    printf("%s\t%u\t%d\n", "*sp     ", &sp, sp);
    
    /* %s is for string fromat
    *  %d is for decimal format
    *  \n new line character
    *  \t horizontal tab
    */
    return (0);
}