C++

File Handling in C++

C++ 132 views Dec 22, 2025 2 min read

File handling in C++ is used to store and retrieve data permanently from files.

File Stream Classes

C++ provides file stream classes in the header.

ClassPurpose
ifstreamRead from file
ofstreamWrite to file
fstreamRead and write

Opening a File

#include

Syntax

ofstream file;
file.open("data.txt");

Or

ofstream file("data.txt");

Writing to a File

ofstream file("data.txt");
file << "Welcome to C++";
file.close();

Reading from a File

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

Reading a Full Line

getline(file, text);

File Opening Modes

ModeDescription
ios::inRead mode
ios::outWrite mode
ios::appAppend mode
ios::binaryBinary file
ios::truncClear file content

Example:

ofstream file("data.txt", ios::app);

Complete Example Program

#include 
#include 
using namespace std;

int main() {
    ofstream fout("sample.txt");
    fout << "File Handling in C++";
    fout.close();

    ifstream fin("sample.txt");
    string data;
    getline(fin, data);
    cout << data>close();

    return 0;
}

Checking File Open Success

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

Advantages of File Handling

  • Permanent data storage

  • Easy data retrieval

  • Useful for large data

Key Points

  • is required

  • Always close files

  • Use correct file modes

  • Supports text and binary files

Conclusion

File handling in C++ allows programs to store data permanently and retrieve it efficiently using file streams.

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