如何让一个输出为.5的浮点数打印为.50？

# 使用格式化字符串
num = 0.5
formatted_num = "{:.2f}".format(num)
print(formatted_num)  # 输出：0.50

# 数字转换
num = 0.5
formatted_num = str(num) + "0"
print(formatted_num)  # 输出：0.50

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

int main() {
    // 使用格式化字符串
    double num = 0.5;
    std::stringstream ss;
    ss << std::fixed << std::setprecision(2) << num;
    std::string formatted_num = ss.str();
    std::cout << formatted_num << std::endl;  // 输出：0.50

    // 数字转换
    num = 0.5;
    std::string str_num = std::to_string(num);
    std::string formatted_num2 = str_num + "0";
    std::cout << formatted_num2 << std::endl;  // 输出：0.50

    return 0;
}