c++ pbkdf2结果正确，但不知道如何从无符号字符进入字符串

#include <iostream>
#include <sstream>

int main() {
    unsigned char data[] = {0x48, 0x65, 0x6C, 0x6C, 0x6F}; // 无符号字符数组
    std::stringstream ss;

    for (int i = 0; i < sizeof(data); i++) {
        ss << data[i]; // 将无符号字符写入字符串流
    }

    std::string result = ss.str(); // 获取转换后的字符串
    std::cout << result << std::endl;

    return 0;
}

#include <iostream>

int main() {
    unsigned char data[] = {0x48, 0x65, 0x6C, 0x6C, 0x6F}; // 无符号字符数组
    std::string result;

    for (int i = 0; i < sizeof(data); i++) {
        result += data[i]; // 将无符号字符拼接到字符串末尾
    }

    std::cout << result << std::endl;

    return 0;
}