使用ifstream、ofstream和fstream
正在尝试将"beave"一词读入文件
稍后将文件内容编辑为用户想要的内容,并将其存储在字符串"line"中
文件从不显示,当我手动检查时,文本文件为空。
#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main()
{
string line = { " " };
ofstream file1;
file1.open("beef.txt");
file1 << "beef" << endl;
file1.close();
file1.open("beef.txt");
if (file1.is_open())
{
cout << "Enter what you would like to be contained in the file" << endl;
cin >> line;
ofstream file1;
file1 << line << endl;
}
return 0;
}
解决方案
Astd::ofstream
仅用于输出,不能用它读取输入。
Astd::ifstream
仅用于输入,您不能用它编写输出。
因此,您需要
使用单独的
std::ofstream
和std::ifstream
变量:int main() { ofstream out_file; ifstream in_file; string line; out_file.open("beef.txt", ios_base::trunc); if (out_file.is_open()) { out_file << "beef" << endl; out_file.close(); } in_file.open("beef.txt"); if (in_file.is_open()) { getline(in_file, line); in_file.close(); cout << "File contains:" << endl; cout << line << endl; } cout << "Enter what you would like to be contained in the file" << endl; getline(cin, line); out_file.open("beef.txt", ios_base::trunc); if (out_file.is_open()) { out_file << line << endl; out_file.close(); } in_file.open("beef.txt"); if (in_file.is_open()) { getline(in_file, line); in_file.close(); cout << "File now contains:" << endl; cout << line << endl; } return 0; }
根据调用
open()
时是否指定了in
和/或out
标志,使用一个std::fstream
变量,该变量可同时用于输出和输入:int main() { fstream file; string line; file.open("beef.txt", ios_base::out | ios_base::trunc); if (file.is_open()) { file << "beef" << endl; file.close(); } file.open("beef.txt", ios_base::in); if (file.is_open()) { getline(file, line); file.close(); cout << "File contains:" << endl; cout << line << endl; } cout << "Enter what you would like to be contained in the file" << endl; getline(cin, line); file.open("beef.txt", ios_base::out | ios_base::trunc); if (file.is_open()) { file << line << endl; file.close(); } file.open("beef.txt", ios_base::in); if (in_file.is_open()) { getline(in_file, line); in_file.close(); cout << "File now contains:" << endl; cout << line << endl; } return 0; }
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