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C

OOP Programs

Practicing small OOP-based programs helps solidify concepts like inheritance, polymorphism, and encapsulation in a practical, hands-on way.

Why practice these?

Practicing small OOP-based programs helps solidify concepts like inheritance, polymorphism, and encapsulation in a practical, hands-on way.

Program 1: Simple Inheritance Example

java
class Employee {
    String name = "Employee";
    void work() {
        System.out.println(name + " is working");
    }
}

class Manager extends Employee {
    Manager() {
        name = "Manager";
    }
}

public class InheritancePractice {
    public static void main(String[] args) {
        Manager m = new Manager();
        m.work();
    }
}

Output:

Manager is working

Program 2: Runtime Polymorphism Example

java
class Shape {
    void area() {
        System.out.println("Calculating area of a shape");
    }
}

class Circle extends Shape {
    void area() {
        System.out.println("Calculating area of a circle");
    }
}

public class PolymorphismPractice {
    public static void main(String[] args) {
        Shape shape = new Circle();
        shape.area();
    }
}

Output:

Calculating area of a circle

Program 3: Encapsulation with Getters and Setters

java
class BankAccount {
    private double balance = 0;

    void deposit(double amount) {
        if (amount > 0) balance += amount;
    }

    double getBalance() {
        return balance;
    }
}

public class EncapsulationPractice {
    public static void main(String[] args) {
        BankAccount account = new BankAccount();
        account.deposit(1500);
        System.out.println("Balance: " + account.getBalance());
    }
}

Output:

Balance: 1500.0

Key Points to Remember

  • Practicing small OOP programs is the best way to internalize how classes, objects, and inheritance actually behave.
  • Try modifying these programs (adding new subclasses or fields) to deepen your understanding further.
  • OOP-based coding questions are extremely common in interviews for freshers and experienced developers alike.