File Handling in C++ with Examples

File Handling in C++

File handling allows programs to store data permanently in files. Unlike variables, file data is not lost when the program ends. C++ provides built-in classes to create, read, write, and update files efficiently.

Why File Handling is Important

Permanent data storage
Data sharing between programs
Data backup and recovery
Handling large data sets

Header File for File Handling

#include <fstream>

This header file provides file-handling classes.

File Handling Classes in C++

C++ provides three main classes:

ofstream – for writing to files
ifstream – for reading from files
fstream – for both reading and writing

Creating and Writing to a File

ofstream file("data.txt");
file << "Welcome to File Handling";
file.close();

Reading from a File

ifstream file("data.txt");
string data;
file >> data;
file.close();

File Open Modes

Mode	Description
ios::in	Read mode
ios::out	Write mode
ios::app	Append mode
ios::binary	Binary mode
ios::trunc	Clear file content

Appending Data to a File

ofstream file("data.txt", ios::app);
file << "New Data";
file.close();

Reading Line by Line

string line;
while(getline(file, line)) {
    cout << line;
}

Checking File Errors

Check if file opened successfully
Handle missing or corrupted files

if(!file) {
    cout << "File not found";
}

Binary File Handling

Used for storing objects and multimedia data.

file.write((char*)&obj, sizeof(obj));

Real-World Applications

Student record systems
Banking applications
Log file management
Data storage systems
Report generation

Common Mistakes to Avoid

Not closing files
Incorrect file modes
File path errors
Ignoring error handling

Advantages of File Handling

Data persistence
Efficient data management
Large data storage
Improved application functionality

Conclusion

File handling in C++ enables permanent data storage using files. By using file streams and modes properly, programmers can efficiently read, write, and manage data. This concept is essential for building real-world, data-driven applications.

File Handling in C++ with Examples