Programming

char *list[];

#include <stdio.h>


int main(void)
{
        char *list[] = {"foo", "bar", "baz"};
        char **pl;
        int len = sizeof(list)/sizeof(&list);
        int i = 0;


        for (pl = list; i < len; i++) {
                printf("%s\n", *pl++);
        }

        /*segfault after baz 
        while ( *pl ) {
                printf("%s\n", *pl++); 
        }
       */

        /*      
        for (i = 0; i < len; i++) {
                printf("%s\n", list[i]); 
        }

        */

        return 0;
}
~

#include <stdio.h>

int main(void)
{       /* Note that list is terminated by a NULL pointer. */
        char *list[] = {"foo", "bar", "baz", NULL};
        char **pl;
        int i;
        /* The common way of setting the number of elements in an array is
        ** to divide the size of the array by the size of the 1st element
        ** in the array.
        */
        int len = sizeof(list)/sizeof(list[0]);

        /* When using 64 bit pointers, each pointer is 8 bytes long. */
        printf("sizeof(list) = %d, sizeof(list[0]) = %d, len = %d\n",
                (int)sizeof(list), (int)sizeof(list[0]), len);

        printf("\nPrinting list using *pl while i < len:\n");
        /* Set pl to the address of the first element in the array list.
        ** Note that in C "list" and "&list[0]" are synonyms.
        */
        for (pl = list, i = 0; i < len; i++, pl++) {
                /* Print the pointer to the pointer. */
                printf("pl = %p\t", pl);        /* &list[i] */
                /* Print the pointed to pointer. */
                printf("*pl = %p\t", *pl);      /* list[i]  */
                /* Print the string pointed to by the pointer to the pointer. */
                printf("%s\n", *pl ? *pl : "NULL pointer");
        }

        printf("\nPrinting list using *pl while *pl != NULL:\n");
        /* If list[]'s last element is not a NULL pointer, this loop will
        ** use random pointers following the array and try to interpret them
        ** as pointers to character strings.  If one of those random values
        ** points outside the address space of the process, we'll get a memory
        ** fault.
        */
        for(pl = list; *pl; printf("%s\n", *pl++));

        printf("\nPrinting list using list[i]:\n");
        for (i = 0; i < len; i++) {
                printf("list[%d] = %p\t", i, list[i]);
                printf("%s\n", list[i] ? list[i] : "NULL pointer");
        }

        return 0;
}

sizeof(list) = 32, sizeof(list[0]) = 8, len = 4

Printing list using *pl while i < len:
pl = 0x7fff6de4db08	*pl = 0x10e24ee70	foo
pl = 0x7fff6de4db10	*pl = 0x10e24ee74	bar
pl = 0x7fff6de4db18	*pl = 0x10e24ee78	baz
pl = 0x7fff6de4db20	*pl = 0x0	NULL pointer

Printing list using *pl while *pl != NULL:
foo
bar
baz

Printing list using list[i]:
list[0] = 0x10e24ee70	foo
list[1] = 0x10e24ee74	bar
list[2] = 0x10e24ee78	baz
list[3] = 0x0	NULL pointer

list++;