File Handling in C++

File handling is one of the most essential skills in C++ programming. Whether you’re building applications that need to store user data, process configuration files, or manage logs, understanding how to work with files is crucial. In this comprehensive guide, we’ll explore the fundamentals of file handling in C++ with practical examples.

File Handling in C++: A Complete Guide to Reading and Writing Files

Why is File Handling Important?

• Data Persistence: Store data permanently beyond program execution
• Configuration Management: Read settings and preferences from files
• Data Processing: Handle large datasets efficiently
• Logging: Record program activities and errors
• Inter-process Communication: Share data between different programs

C++ File Stream Classes:

C++ provides three main classes for file operations:

1. ofstream (Output File Stream): Used for writing data to files
2. ifstream (Input File Stream): Used for reading data from files
3. fstream (File Stream): Used for both reading and writing operations

Practical Example: Writing and Reading a Text File

#include <iostream>
#include<fstream>
using namespace std;
int main() {
   ofstream Writefile("File_name.txt");
   Writefile<<"Writing to the file";
   Writefile.close();
   string ans;
   ifstream Readfile("File_name.txt");
   while(getline(Readfile,ans)){
       cout<<ans;
   }
   Readfile.close();
   

    return 0;
}

How It Works

Writing Part:

1. ofstream Writefile("File_name.txt") – Creates/opens a file for writing
2. Writefile << "Writing to the file" – Writes text to the file
3. Writefile.close() – Closes the file

Reading Part:

1. ifstream Readfile("File_name.txt") – Opens the file for reading
2. getline(Readfile, ans) – Reads each line from the file
3. cout << ans – Displays the content on screen
4. Readfile.close() – Closes the file

Real-World Applications

File handling is used everywhere:

• Saving game progress and user settings
• Processing CSV data and configuration files
• Creating application logs and error reports
• Storing database records and user data