SS_string.c

#include "shell.h"
/**
 * _strlen - this function calculate the lenght of a string by iterating over
 * each character until the null terminator is encounter
 * @s: parameter showing the string whose length to be checked
 * Return: the lenght of a string
 */
int _strlen(char *s)
{
	int length = 0;

	if (!s)
		return (0);

	while (*s++)
		length++;

	return (length);
}

/**
 * _strcmp - thid function does lexicogarphic comparison of two strings.
 * @s1: parameter showing the first string to be compared
 * @s2: parameter showing the second string to be compared
 * Return: 0 if successful
 */

int _strcmp(char *s1, char *s2)
{
	while (*s1 && *s2)
	{
		if (*s1 != *s2)
			return (*s1 - *s2);
		s1++;
		s2++;
	}
	if (*s1 == *s2)
		return (0);
	else
		return (*s1 < *s2 ? -1 : 1);

}

/**
 * starts_with - this function checks if a sting is a prefix of another string
 * @haystack: parameter indicating the string to search
 * @needle: function parameter showing the substring to find
 * Return: 0 if successful
 */

char *starts_with(const char *haystack, const char *needle)
{
	while (*needle)
	{
		if (*needle != *haystack)
			return (NULL);
		needle++;
		haystack++;
	}

	return ((char *) haystack);
}

/**
 * _strcat - this function concatenates two strings by appending one to the end
 * of another
 * @dest: parameter showing the destination buffer
 * @src: function parameter indicating the source buffer
 * Return: 0 if successful
 */

char *_strcat(char *dest, char *src)
{
	char *a = dest;

	while (*dest)
		dest++;

	while (*src)
	{
		*dest = *src;
		dest++;
		src++;
	}
	return (a);
}