How to read and write text files using C++?

To read and write text files in C++, you can use the fstream library. Specific steps: 1. Open the file: open the file in input mode (ifstream) for reading, open the file in output mode (ofstream) for writing or append writing. 2. Read the file: Use the operator>> operator to read the file content line by line. 3. Write to file: Use operator

Reading and writing text files using C++

Text files are a simple way to store data in human-readable text. In C++, text files can be read and written using the fstream library.

Open a text file

To open a text file, you can use ifstream (input file stream) or ofstream (output file stream) file stream) class. For example:

// 打开文件以进行读取
ifstream infile("input.txt");

// 打开文件以进行写入（覆盖现有文件）
ofstream outfile("output.txt");

// 打开文件以进行追加（在文件末尾写入）
ofstream outfile("output.txt", ios::app);

Read a text file

To read a text file, you can use the operator>> operator, for example:

string line;
while (getline(infile, line)) {
  // 处理文件中的每一行
}

Write a text file

To write a text file, you can use the operator<< operator, for example:

outfile << "Hello, world!" << endl;

Practical Case

The following program reads a text file and prints its contents:

#include <fstream>
#include <iostream>

using namespace std;

int main() {
  // 打开文件以进行读取
  ifstream infile("input.txt");

  // 读取文件内容
  string line;
  while (getline(infile, line)) {
    cout << line << endl;
  }

  return 0;
}

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