如何在C ++中向文件添加多行？

Question

我是C ++的新手，并在控制台上写了一些待办事项清单。我只能在文本文件中添加一行，但是当我尝试添加更多行时，它将不会出现在我的文本文件中。

请看一下我在做什么错

//output-file stream
    ofstream file;
    file.open("output.txt", std::ios_base::app); //append

    bool isRunning = true;

    while (isRunning) {
        cout << "Please select an action:" << endl;
        cout << "add - adding tasks to the list" << endl;
        cout << "del - deleting tasks to the list" << endl;
        cout << "list - show the list" << endl;
        cout << "x - to exit program" << endl;

        string input;
        cin >> input; 
        string addedTask;

        if (input == "add") {
            cout << "Please enter a task you like to add: " << endl;
            cin.ignore();
            if (std::getline(std::cin, addedTask)) {
                file << addedTask << "\n";
            }
            else {
                cout << "Failed to read line" << endl;
            }
        }

为什么我只能添加一个字符串行？我仍然无法解决问题，或者我缺少什么？

Answer 1

尝试一下。输入“ x”终止程序。

#include <stdio.h>
#include <stdlib.h>
#include<string>
#include <cstring>
#include <fstream>
#include <iostream>
using namespace std;
int main()
{
    ofstream file;
    file.open("output.txt", std::ios_base::app); //append

    while (1) {
        cout << "Please select an action:" << endl;
        cout << "add - adding tasks to the list" << endl;
        cout << "del - deleting tasks to the list" << endl;
        cout << "list - show the list" << endl;
        cout << "x - to exit program" << endl;

        string input;
        cin >> input;
        string addedTask;

        if (input == "add") {
            cout << "Please enter a task you like to add: " << endl;
            cin.ignore();
            if (std::getline(std::cin, addedTask)) {
                file << addedTask << "\n";
            }
            else {
                cout << "Failed to read line" << endl;
            }
        }
        else if (input == "x")
        {
            break;
        }
    }
    file.close();
    return 0;
}