在C++中比较两个字符串有困难

#include <iostream>
#include <cstring>

int main() {
    char str1[] = "Hello";
    char str2[] = "World";

    int result = strcmp(str1, str2);

    if (result == 0) {
        std::cout << "两个字符串相等" << std::endl;
    } else if (result < 0) {
        std::cout << "第一个字符串小于第二个字符串" << std::endl;
    } else {
        std::cout << "第一个字符串大于第二个字符串" << std::endl;
    }

    return 0;
}

#include <iostream>
#include <cstring>

int main() {
    char str1[] = "Hello";
    char str2[] = "World";

    int result = strncmp(str1, str2, 3);

    if (result == 0) {
        std::cout << "两个字符串相等" << std::endl;
    } else if (result < 0) {
        std::cout << "第一个字符串小于第二个字符串" << std::endl;
    } else {
        std::cout << "第一个字符串大于第二个字符串" << std::endl;
    }

    return 0;
}

#include <iostream>
#include <string>

int main() {
    std::string str1 = "Hello";
    std::string str2 = "World";

    if (str1 == str2) {
        std::cout << "两个字符串相等" << std::endl;
    } else if (str1 < str2) {
        std::cout << "第一个字符串小于第二个字符串" << std::endl;
    } else {
        std::cout << "第一个字符串大于第二个字符串" << std::endl;
    }

    return 0;
}