C++ ifstream UTF8的第一个字符

#include<iostream>
#include <fstream>
#include<string>

int main() {
    std::ifstream file("test.txt", std::ios::binary);
    if (!file.is_open()) {
        std::cout << "Failed to open file"<< std::endl;
        return 1;
    }

    // Read the first character of the file
    unsigned char first_byte;
    file.get(first_byte);

    // Check if the first byte is a UTF-8 BOM (byte order mark)
    if (first_byte == 0xEF) {
        unsigned char second_byte;
        file.get(second_byte);
        if (second_byte == 0xBB) {
            unsigned char third_byte;
            file.get(third_byte);
            if (third_byte == 0xBF) {
                std::cout << "The file has a UTF-8 BOM"<< std::endl;
            } else {
                std::cout << "The file is not UTF-8 encoded"<< std::endl;
            }
        } else {
            std::cout << "The file is not UTF-8 encoded"<< std::endl;
        }
    } else {
        std::cout << "The file is not UTF-8 encoded"<< std::endl;
    }

    file.close();
    return 0;
}