#include <Windows.h> 
#include <stdio.h>  
#include <tchar.h> 
  
int strlen_my1(char s[]) 
{ 
    char* p = s; 
    while (*p++); 
    return p - s - 1; 
} 
 
int strlen_my2(char* s) { 
    char* p = s; 
    while (*p != '\0') { 
        p++; 
    } 
    return p - s; 
} 
 
int strcmp_my(const char str1[], const char str2[]) { 
    int i = 0; 
    while (str1[i] != '\0' && str2[i] != '\0' && str1[i] == str2[i]) 
        i++; 
    return str1[i] - str2[i]; 
} 
 
void strcpy_my(char* dest, char* src) 
{ 
    while (*dest++ = *src++); 
} 
 
void strcat_my(char* dest, char* src) { 
    while (*dest) dest++; 
 
    while (*src) { 
        *dest = *src; 
        dest++; 
        src++; 
    } 
 
    *dest = '\0'; 
} 
 
void strchr_my(const char* str, int c, char** result) { 
    while (*str != '\0') { 
        if (*str == c) { 
            *result = (char*)str; 
            return; 
        } 
        str++; 
    } 
} 
 
void test_strchr_my() { 
    const char* str1 = "Hello, World!"; 
    const char* str2 = "This is a test string."; 
 
    // Пример 1: Поиск символа 'o' в строке "Hello, World!" 
    char* result1 = NULL; 
    strchr_my(str1, 'o', &result1); 
    if (result1 != NULL) { 
        printf("%ld\n", result1 - str1); 
    } 
    else { 
        printf("NULL\n"); 
    } 
 
    // Пример 2: Поиск символа 'z' в строке "This is a test string." 
    char* result2 = NULL; 
    strchr_my(str2, 'z', &result2); 
    if (result2 != NULL) { 
        printf("%ld\n", result2 - str2); 
    } 
    else { 
        printf("NULL\n"); 
    } 
}