Java Program to Calculate Interest For FDs, RDs using Inheritance

Inheritance is an important pillar of OOP(Object-Oriented Programming). It is the mechanism in java by which one class is allowed to inherit the features(fields and methods) of another class. In this article, we will create an application to calculate interest for FDs, RDs based on certain conditions using inheritance. Create three classes in a single package. Create their member function. Create a Menu Driven Program. 

Steps

1. Create the Main Java File to take input of the choices on Interest Calculator like for Saving account, fixed deposit account, Recurring Deposits.
2. Create Another Class to calculate the Interest of fixed deposit. Calculate the FD Interest by Formula = FDAmount * FDinterestRate.
3. Also, Check If the Interest is Applicable in for normal Citizen Of the Senior Citizen. Create Another Class to calculate the Interest of Saving deposit. Calculate the saving account Interest by Formula = Amount * SavingAccountinterestRate. Also, check if it’s a Normal Account or an NRI Account.
4. Create Another Class to calculate the Interest of Recurring Deposits. Calculate the RD Interest by Formula = RDAmount * RDinterestRate.
5. Also, Check The Months and the holder’s age to Calculate the Interest. 

Flow Diagram

Code

Account.Java

Java

package College;

public abstract class Account {

    double interestRate;
    double amount;

    abstract double calculateInterest(double amount)
        throws InvalidMonthsException, InvalidAgeException,
               InvalidAmountException, InvalidDaysException;
}

IntrestCalculator.java

Java

package College;

import java.util.Scanner;

public class InterestCalculator {
    public static void main(String[] args)
    {
        // TODO code application logic here
        Scanner sc = new Scanner(System.in);
        System.out.println(
            "SELECT THE OPTIONS "
            + "\n1."
            + " Interest Calculator-Saving
              Account " + " \n2." + " Interest Calculator
            - Fixed Deposit "
            + "\n3."
            + " InterestCalculator-Recurring Deposits"
            + "\n4 "
            + " Exit");
        int choice = sc.nextInt();
        switch (choice) {
        case 1:
            SBaccount sb = new SBaccount();
            try {
                System.out.println(
                    "Enter the Average SB amount ");
                double amount = sc.nextDouble();
                System.out.println(
                    "Interest gained is : $ "
                    + sb.calculateInterest(amount));
            }
            catch (InvalidAmountException e) {
                System.out.println(
                    "Exception : Invalid amount");
            }
            break;
        case 2:
            try {
                FDaccount fd = new FDaccount();
                System.out.println("Enter the FD Amount");
                double fAmount = sc.nextDouble();
                System.out.println(
                    "Interest gained is: $ "
                    + fd.calculateInterest(fAmount));
            }
            catch (InvalidAgeException e) {
                System.out.println("Invalid Age Entered");
            }
            catch (InvalidAmountException e) {
                System.out.println(
                    "Invalid Amount Entered");
            }
            catch (InvalidDaysException e) {
                System.out.println("Invalid Days Entered");
            }
            break;
        case 3:
            try {
                RDaccount rd = new RDaccount();
                System.out.println("Enter the RD amount");
                double Ramount = sc.nextDouble();
                System.out.println(
                    "Interest gained is: $ "
                    + rd.calculateInterest(Ramount));
            }
            catch (InvalidAgeException e) {
                System.out.println("Invalid Age Entered");
            }
            catch (InvalidAmountException e) {
                System.out.println(
                    "Invalid Amount Entered");
            }
            catch (InvalidMonthsException e) {
                System.out.println("Invalid Days Entered");
            }
            break;
        case 4:
            System.out.println(
                "DO YOU WANT TO CALCULATE AGAIN ????"
                + " "
                + "RUN AGAIN THE PROGRAM");
        default:
            System.out.println("Wrong choice");
        }
    }
}

FDaAccount.java

Java

package College;

import java.util.Scanner;

public class FDaccount extends Account {
    double FDinterestRate;
    double FDAmount;
    int noOfDays;
    int ageOfACHolder;
    double General, SCitizen;
    Scanner FDScanner = new Scanner(System.in);
    @Override
    double calculateInterest(double amount)
        throws InvalidAgeException, InvalidAmountException,
               InvalidDaysException
    {
        this.FDAmount = amount;
        System.out.println("Enter FD days");
        noOfDays = FDScanner.nextInt();
        System.out.println("Enter FD age holder ");
        ageOfACHolder = FDScanner.nextInt();
        if (amount < 0) {
            throw new InvalidAmountException();
        }
        if (noOfDays < 0) {
            throw new InvalidDaysException();
        }
        if (ageOfACHolder < 0) {
            throw new InvalidAgeException();
        }
        if (amount < 10000000) {
            if (noOfDays >= 7 && noOfDays <= 14) {
                General = 0.0450;
                SCitizen = 0.0500;
            }
            else if (noOfDays >= 15 && noOfDays <= 29) {
                General = 0.0470;
                SCitizen = 0.0525;
            }
            else if (noOfDays >= 30 && noOfDays <= 45) {
                General = 0.0550;
                SCitizen = 0.0600;
            }
            else if (noOfDays >= 45 && noOfDays <= 60) {
                General = 0.0700;
                SCitizen = 0.0750;
            }
            else if (noOfDays >= 61 && noOfDays <= 184) {
                General = 0.0750;
                SCitizen = 0.0800;
            }
            else if (noOfDays >= 185 && noOfDays <= 365) {
                General = 0.0800;
                SCitizen = 0.0850;
            }
            FDinterestRate
                = (ageOfACHolder < 50) ? General : SCitizen;
        }
        else {
            if (noOfDays >= 7 && noOfDays <= 14) {
                interestRate = 0.065;
            }
            else if (noOfDays >= 15 && noOfDays <= 29) {
                interestRate = 0.0675;
            }
            else if (noOfDays >= 30 && noOfDays <= 45) {
                interestRate = 0.00675;
            }
            else if (noOfDays >= 45 && noOfDays <= 60) {
                interestRate = 0.080;
            }
            else if (noOfDays >= 61 && noOfDays <= 184) {
                interestRate = 0.0850;
            }
            else if (noOfDays >= 185 && noOfDays <= 365) {
                interestRate = 0.10;
            }
        }
        return FDAmount * FDinterestRate;
    }
}

RDaccount.java

Java

package College;

import java.util.Scanner;

public class RDaccount extends Account {
    double RDInterestRate;
    double RDamount;
    int noOfMonths;
    double monthlyAmount;
    double General, SCitizen;
    Scanner RDScanner = new Scanner(System.in);
    @Override
    double calculateInterest(double Ramount)
        throws InvalidMonthsException,
               InvalidAmountException, InvalidAgeException
    {
        this.RDamount = Ramount;
        System.out.println("Enter RD months");
        noOfMonths = RDScanner.nextInt();
        System.out.println("Enter RD holder age");
        int age = RDScanner.nextInt();
        if (RDamount < 0) {
            throw new InvalidAmountException();
        }
        if (noOfMonths < 0) {
            throw new InvalidMonthsException();
        }
        if (age < 0) {
            throw new InvalidAgeException();
        }
        if (noOfMonths >= 0 && noOfMonths <= 6) {
            General = .0750;
            SCitizen = 0.080;
        }
        else if (noOfMonths >= 7 && noOfMonths <= 9) {
            General = .0775;
            SCitizen = 0.0825;
        }
        else if (noOfMonths >= 10 && noOfMonths <= 12) {
            General = .0800;
            SCitizen = 0.0850;
        }
        else if (noOfMonths >= 13 && noOfMonths <= 15) {
            General = .0825;
            SCitizen = 0.0875;
        }
        else if (noOfMonths >= 16 && noOfMonths <= 18) {
            General = .0850;
            SCitizen = 0.0900;
        }
        else if (noOfMonths >= 22) {
            General = .0875;
            SCitizen = 0.0925;
        }
        RDInterestRate = (age < 50) ? General : SCitizen;
        return RDamount * RDInterestRate;
    }
}

SBaccount.Java

Java

package College;

import java.util.Scanner;

class SBaccount extends Account {
    double SBamount, SbInterestRate, interest;
    Scanner SBScanner = new Scanner(System.in);
    @Override
    double calculateInterest(double amount)
        throws InvalidAmountException
    {
        this.SBamount = amount;
        if (SBamount < 0) {
            throw new InvalidAmountException();
        }
        System.out.println(
            "Select account type \n1. NRI \n2. Normal ");
        int accountChoice = SBScanner.nextInt();
        switch (accountChoice) {
        case 1:
            SbInterestRate = .06;
            break;
        case 2:
            SbInterestRate = .04;
            break;
        default:
            System.out.println(
                "Please choose right account again");
        }
        return amount * SbInterestRate;
    }
}

Output