从文件中读取双精度值

with open('file.txt', 'r') as f:
    double_value = float(f.read())

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class ReadDoubleFromFile {
    public static void main(String[] args) {
        try {
            FileReader fileReader = new FileReader("file.txt");
            BufferedReader bufferedReader = new BufferedReader(fileReader);
            double doubleValue = Double.parseDouble(bufferedReader.readLine());
            bufferedReader.close();
            System.out.println(doubleValue);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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

int main() {
    std::ifstream file("file.txt");
    double double_value;
    file >> double_value;
    file.close();
    std::cout<< double_value<< std::endl;
    return 0;
}