How to delete content at a specified location in a file using C++?

The erase() function in C++ is used to delete content from a file. The syntax is stream.erase(streampos start_pos, streampos end_pos). When using the erase() function, you need to specify the starting position and ending position (byte offset) of the deleted content.

How to use the erase() function in C++ to delete content from a file

The C++ library provides a variety of methods to operate File, which includes the erase() function, which allows you to delete a specific range of content from a file.

Syntax:

stream.erase(streampos start_pos, streampos end_pos);

• stream: File stream object
• start_pos: To The starting position of the content to be deleted (byte offset)
• end_pos: The end position of the content to be deleted (byte offset)

Practical case:

Suppose we have a file named "data.txt" that contains the following text:

This is a sample text file.
Hello, world!

To remove "Hello, world!" from the file! " line, you can use the following code:

#include <fstream>
#include <iostream>

using namespace std;

int main() {
  // 打开文件，用于读写
  fstream file("data.txt", ios::in | ios::out);

  if (!file.is_open()) {
    cout << "无法打开文件！" << endl;
    return 1;
  }

  // 定位到要删除内容的起始位置
  file.seekg(16);

  // 定位到要删除内容的结束位置
  file.seekp(27);

  // 删除指定范围的内容
  file.erase(file.tellg(), file.tellp());

  // 关闭文件
  file.close();

  cout << "删除操作成功！" << endl;

  return 0;
}

After running this code, the file "data.txt" will look like this:

This is a sample text file.

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