c++ string转hex

可以使用stringstream和iomanip库将c++ string转换为hex格式。具体实现如下：

#include <iostream>
#include <string>
#include <sstream>
#include <iomanip>

int main() {
    std::string str = "hello world";
    std::stringstream ss;
    for (size_t i = 0; i < str.size(); ++i) {
        ss << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(str[i]);
    }
    std::string hex_str = ss.str();
    std::cout << hex_str << std::endl; // 输出：68656c6c6f20776f726c64
    return 0;
}