Prev Next

Java While Loops: Real-Life Examples

Applying while loops in real-world scenarios can help you understand their practical use. Below are examples demonstrating how while loops can be used in applications.

1. User Input Validation

Using a do/while loop to repeatedly prompt the user until valid input is received.

import java.util.Scanner;

public class InputValidation {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int age;
        do {
            System.out.print("Enter your age (1-120): ");
            age = scanner.nextInt();
        } while (age < 1 || age > 120);
        System.out.println("Your age is: " + age);
        scanner.close();
    }
}

Output:

Enter your age (1-120): 130
Enter your age (1-120): 25
Your age is: 25

Using a while loop to display a menu and perform actions based on user choice until the user decides to exit.

import java.util.Scanner;

public class MenuProgram {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int choice;
        do {
            System.out.println("Menu:");
            System.out.println("1. Option 1");
            System.out.println("2. Option 2");
            System.out.println("3. Exit");
            System.out.print("Enter your choice: ");
            choice = scanner.nextInt();

            switch (choice) {
                case 1:
                    System.out.println("You selected Option 1.");
                    break;
                case 2:
                    System.out.println("You selected Option 2.");
                    break;
                case 3:
                    System.out.println("Exiting...");
                    break;
                default:
                    System.out.println("Invalid choice. Try again.");
            }
        } while (choice != 3);
        scanner.close();
    }
}

Output:

Menu:
1. Option 1
2. Option 2
3. Exit
Enter your choice: 1
You selected Option 1.
Menu:
1. Option 1
2. Option 2
3. Exit
Enter your choice: 3
Exiting...

3. File Processing

Using a while loop to read data from a file until the end of the file is reached.

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class FileReadingExample {
    public static void main(String[] args) {
        try (BufferedReader br = new BufferedReader(new FileReader("data.txt"))) {
            String line;
            while ((line = br.readLine()) != null) {
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Output:

Line 1
Line 2
Line 3

Key Takeaways

  • While loops are versatile and can be used in various real-life applications.
  • They are ideal for situations where the number of iterations depends on dynamic conditions.
  • Understanding practical examples enhances your ability to implement loops effectively.
Prev Next