Q9. Demonstrate File Handling in C++

Question:
Write a program to demonstrate file handling.

My Approach

File handling ka matlab hota hai ki program directly file se data read aur write kar sake.
C++ me iske liye teen important classes hoti hain (header <fstream> ke andar):

ofstream → File me likhne (Write) ke liye.
ifstream → File se padne (Read) ke liye.
fstream → File ko dono tarah (read + write) ke liye.

Program Code

File Name: file_handling_demo.cpp


#include <iostream>
#include <fstream>
using namespace std;
 
int main() {
    string name;
    int rollNo;
    float marks;
 
    // File me data likhna
    ofstream outFile("student.txt"); // file create/open
    if (!outFile) {
        cout << "File could not be opened for writing!" << endl;
        return 1;
    }
 
    cout << "Enter Student Name: ";
    getline(cin, name);
    cout << "Enter Roll No: ";
    cin >> rollNo;
    cout << "Enter Marks: ";
    cin >> marks;
 
    outFile << "Name: " << name << endl;
    outFile << "Roll No: " << rollNo << endl;
    outFile << "Marks: " << marks << endl;
 
    outFile.close(); // file band karna zaroori hai
 
    cout << "\nData successfully written to student.txt\n" << endl;
 
    // File se data read karna
    ifstream inFile("student.txt");
    if (!inFile) {
        cout << "File could not be opened for reading!" << endl;
        return 1;
    }
 
    cout << "=== Reading Data from File ===" << endl;
    string line;
    while (getline(inFile, line)) {
        cout << line << endl;
    }
 
    inFile.close();
 
    return 0;
}

Sample Output


Enter Student Name: Intesab Ansari
Enter Roll No: 101
Enter Marks: 89.5

Data successfully written to student.txt

=== Reading Data from File ===
Name: Intesab Ansari
Roll No: 101
Marks: 89.5

Explanation

ofstream outFile("student.txt"); → File create hoti hai aur usme data write hota hai.
ifstream inFile("student.txt"); → Same file se data read hota hai.
getline(inFile, line) → File ko line by line read karta hai.
close() function ka use karna zaroori hota hai memory aur resources free karne ke liye.

Real-Life Scenario

Example: Jab tumhare college ke students ka data maintain karna ho:
- Name, Roll No, Marks ko ek file me store karna.
- Later wo file se read karke result generate karna.

Yehi kaam hamne program me kiya hai.

Conclusion

File handling C++ me input/output ko persistent storage (files) ke saath connect karta hai.
ofstream, ifstream, aur fstream ka use karke data read aur write karna easy ho jata hai.

Submitted by:
Intesab Ansari
MCA Student, NMU University
Portfolio: intesab.live