Point 2

/*      Introduction to program:
        Program - point2.c.
        Example of the use of pointers and arrays.
        Francis O'Donovan 16-1-98. */

/* Files to be included. */

#include <stdio.h>

/* Function: main(). */

main()
{
/* Initialize variables. */

        int i;          /* Counter for for loop. */
        int j;          /* Used in for loop. */
        int z[10];      /* An integer array of size 10. */
        int *p;         /* A pointer to an integer. */

/* Print introduction on screen. */

        printf( "Program: point2.c.\n" );
        printf( "Example of the use of pointers and arrays.\n" );
        printf( "Francis O'Donovan 16-1-98.\n\n" );

/* Initialize array. */

        printf( "** The initial array values, " );
        printf( "initialized using a for loop **\n\n" );

        for( i = 0; i<10; i++ )
        {
                z[i] = i+5;       /* z[0] = 5, z[1] = 6,..., z[9] = 14. */

                /* Print out the value and address of the ith element. */

                printf( "The value of z[%d] is %d. ", i, z[i] );
                printf( "The address of z[%d] is %d.\n", i, &(z[i]) );

        }

/* Set p to point to the array. */

p = z;

/* Print out value and address of p. */

        printf( "\n** Pointer p **\n\n" );
        printf( "The value of p is %d, and its address is %d.\n", p, &p );
        printf( "The value of p is equal to the address of z[0].\n" );
        printf( "This is because setting a pointer to point to an array means setting " );
        printf( "it to point to the array's first element.\n\n" );

        /* Modify array to 7 through 16, using pointer. */

        for ( i = 0; i<10; i++ )
        {
                *p = i+7;     /* z[0] = 7, z[1] = 8, etc.. */
                p++;
        }

        /* Print out new values in array. */

        printf( "** The new array values **\n\n" );

        for( i = 0; i<10; i++ )
        {
                printf( "The value of z[%d] is %d.\n", i, z[i] );
        }

}

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