PRACTICE QUESTIONS ON ABSTRACT CLASS – CLASS BANK CALCULATE INTEREST

Create an abstract class “Account” with abstract method “calculateInterest()”. Implement two subclasses “SavingsAccount” and “CurrentAccount” which extend “Account” and implement the “calculateInterest()” method. Create objects of both classes and test their behavior.

Solution :

abstract class Account {
    protected double balance;

    public Account(double balance) {
        this.balance = balance;
    }

    public abstract double calculateInterest();
}

class SavingsAccount extends Account {
    public SavingsAccount(double balance) {
        super(balance);
    }

    public double calculateInterest() {
        double interest = balance * 0.05; // 5% interest rate
        balance += interest;
        return interest;
    }
}

class CurrentAccount extends Account {
    public CurrentAccount(double balance) {
        super(balance);
    }

    public double calculateInterest() {
        // Current account doesn't have interest
        return 0.0;
    }
}

public class AbstractExample {
    public static void main(String[] args) {
        Account savingsAccount = new SavingsAccount(1000.0);
        Account currentAccount = new CurrentAccount(2000.0);

        // Print initial balance
        System.out.println("Savings Account Balance: " + savingsAccount.balance);
        System.out.println("Current Account Balance: " + currentAccount.balance);

        // Calculate interest and print balance
        double savingsInterest = savingsAccount.calculateInterest();
        double currentInterest = currentAccount.calculateInterest();
        System.out.println("Savings Account Balance after interest: " + savingsAccount.balance);
        System.out.println("Interest earned on Savings Account: " + savingsInterest);
        System.out.println("Current Account Balance after interest: " + currentAccount.balance);
        System.out.println("Interest earned on Current Account: " + currentInterest);
    }
}

Save the above Program with “AbstractExample .Java” then compile it with the following command :

javac AbstractExample.java //to compile the code 

java AbstractExample //to run the code

Output is :

Savings Account Balance: 1000.0
Current Account Balance: 2000.0
Savings Account Balance after interest: 1050.0
Interest earned on Savings Account: 50.0
Current Account Balance after interest: 2000.0
Interest earned on Current Account: 0.0

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