#include<stdio.h>

size_t strlen(const char* s){
	size_t len = 0;
	while(*s){
		++s;
		++len;
	}
	return len;
}

/* Return 0 if the strings are the same
 * Return -1 if a comes before b
 * Return 1 if b comes before a
 */
int strcmp(const char* a, const char* b){
	while(*a++ == *b++ && *a && *b);
	if(*a == 0 && *b == 0)
		return 0;
	if(*a > *b)
		return 1;
	return 0;
}

/* Parameters:  Destination, source */
void strcpy(char *dest, const char* src){
	printf("This is our strcpy\n");
	while(*dest++ = *src++);
}

char* strchr(char* haystack, char needle){
	for(;*haystack && *haystack != needle; ++haystack);
	if(*haystack)
		return haystack;
	return 0;
}


int main(){
	const char *animal = "giraffe";
	printf("%s\n", animal);
	char canimal[] = "giraffe";
	printf("%s\n", canimal);

	if(strcmp(animal, canimal) == 0)
		printf("both are equal\n");
	else
		printf("%s != %s\n", animal, canimal);

	if(strcmp("fox", "dog") > 0)
		printf("dog comes first\n");
	else
		printf("fox comes first\n");
	printf("The length of animal is %d\n", strlen(animal));

	char copy[strlen(canimal)];
	strcpy(copy, canimal);
	copy[1] = 'Y';
	printf("canimal = %s, copy = %s\n", canimal, copy);
	
	if(strchr(animal, 'e'))
		printf("animal contains an e\n");
	if(strchr(animal, 'z'))
		printf("animal contains a z\n");
	*(strchr(canimal, 'r')) = 'R';
	printf("canimal = %s\n", canimal);

	return 0;


}