---

#include "s21_string.h"

size_t s21_strlen(const char *str) {
    size_t length = 0;

    while (str[length] != '\0') {
        length++;
    }

    return length;
}

int s21_strcmp(const char *str1, const char *str2) {
    while (*str1 && *str1 == *str2) {
        str1++;
        str2++;
    }

    return (unsigned char)*str1 - (unsigned char)*str2;
}

char *s21_strcpy(char *dest, const char *src) {
    char *start = dest;

    while ((*dest++ = *src++) != '\0') {
    }

    return start;
}

char *s21_strcat(char *dest, const char *src) {
    char *start = dest;

    while (*dest != '\0') {
        dest++;
    }

    while ((*dest++ = *src++) != '\0') {
    }

    return start;
}