/*
 * Program to find length of string, several ways.
 * Also illustrates use of strcpy to copy a string and
 * strcmp to compare two strings.
 */
#include <stdio.h>
#include <string.h>

#define SIZE 80

/* operate on string using array index */
int strlen_array(char s[]) {
	int count = 0;
	while (s[count] != '\0') { 
		count+=1;
	}
	return count;
}

/* operate on string using pointer */
int strlen_pointer(char *s) {
	char *p = s;
	while (*p != '\0') { 
		++p;
	}
	return p-s;
}

/* operate on string using pointer and recursion */
int strlen_recursive(char *s) {
	if (*s == '\0') {
		return 0;
	}
	else {
		return 1 + strlen_recursive(s+1);
	}
}

int main(void) {
	printf("enter line\n");
	char line[SIZE];
	fgets(line, SIZE, stdin);
	/* was the line too long? */
	char *endline = strchr(line, '\n');
	if (endline == NULL) {
		printf("line too long\n");
        return 1;
	}
	*endline = '\0';
	printf("line is '%s'\n", line);
	printf("strlen_array %d\n", strlen_array(line));
	printf("strlen_pointer %d\n", strlen_pointer(line));
	printf("strlen_recursive %d\n", strlen_recursive(line));
	printf("library strlen %d\n", (int) strlen(line));

	char copy[SIZE];
	strcpy(copy, line);
	printf("copy is '%s'\n", copy);

	if (strcmp(copy, line) == 0) {
		printf("equal\n");
	} 
	else {
		printf("not equal\n");
	}
		
	return 0;
}