Accessing arrays via pointers

/* 1603.c: Accessing arrays via pointers */
#include <stdio.h>

main()
{
    char str[] = "It's a string!";
    char *ptr_str;
    int list[] = {1, 2, 3, 4, 5};
    int *ptr_int;

    /* access char array */
    ptr_str = str;
    printf("Before the change, str contains: %s\n", str);
    printf("Before the change, str[5] contains: %c\n", str[5]);
    *(ptr_str + 5) = 'A';
    printf("After the change, str[5] contains: %c\n", str[5]);
    printf("After the change, str contains: %s\n", str);
    /* access int array */
    ptr_int = list;
    printf("Before the change, list[2] contains: %d\n", list[2]);
    *(ptr_int + 2) = -3;
    printf("After the change, list[2] contains: %d\n", list[2]);

    return 0;
}