string & list of string in C

string.c

#include <stdio.h>

int
main()
{
    /* character */
    char a;
    a = 's';
    printf("char a\t= %c\n", a);

    /* string is an array of character */
    char s1[] = "hello";
    printf("s1[]\t= %s\n", s1);
    printf("s1[0]\t= %c\n", s1[0]); // h
    printf("*(s1)\t= %c\n", *(s1)); // h
    printf("*(s1+4)\t= %c\n", *(s1+4)); // o

    char s2[] = {'h', 'e', 'l', 'l', 'o', '\0'};
    printf("s2[]\t= %s\n", s2);
    printf("s2[1]\t= %c\n", s2[0]); // h
    printf("*(s2+1)\t= %c\n", *(s2+1)); // e

    /* string is a pointer to character */
    char *s3 = "hello";
    printf("s3\t= %s\t| mem = %d\n", s3, *s3);
    printf("s3+1\t= %s\t| mem = %d\n", s3+1, *(s3 + 1)); // ello
    printf("*(s3)\t= %c\n", *(s3)); // h
    printf("s3[0]\t= %c\n", s3[0]); // h
    
    /* difference: http://stackoverflow.com/a/1704433/3376568*/

    /* pointer to "array of character" or
     * array of pointer to character is a list of string */
    char *s4[2];
    s4[0] = "hello";
    s4[1] = "world";
    printf("*s4[2]\t= %s %s\n", s4[0], s4[1]);

    /* pointer to "pointer to character" is a list of string */
    char **s5;
    s5[0] = "hello";
    s5[1] = "world";
    printf("**s5\t= %s %s\n", s5[0], s5[1]);

    /* array of "array of character" is a list of string */
    char s6[2][6] = {{'h', 'e', 'l', 'l', 'o', '\0'}, {'w', 'o', 'l', 'd', '\0'}};
    printf("s6[2][6]\t= %s %s\n", s6[0], s6[1]);
}