Convert String to Bits in C

string_to_bits.c

char * convertStringToBits(char * string) {
    int i;
    int stringLength = strlen(string);
    int mask = 0x80; /* 10000000 */
    char *charArray;
    charArray = malloc(8 * stringLength + 1);
    if(charArray == NULL) {
        printf("An error occured!\n");
        return NULL; //error - cant use charArray
    }

    for(i = 0; i < stringLength; i++) {
        mask = 0x80;
        char c = string[i];
        int x = 0;
        while(mask > 0) {
            char n = (c & mask) > 0;
            printf("%d", n);
            charArray[x++] = n;
            mask >>= 1; /* move the bit down */
        }
        printf("\n");
    }

    return charArray;
}