Question

Create a Java Program/Class named ComputeInterest to calculate compound interest.

This can all be done entirely in the main() method.

Create a double variable named currentBalance.

1. Create a double variable named newBalance.
2. Create a final double variable named INTEREST_RATE and assign 1.05 to it.
3. Create a int variable named yearCount.
4. Prompt for the "Number of years to invest" and store the input into the yearCount variable.
5. Prompt for the "Amount to Invest" and store this in the currentBalance variable.
6. Assign currentBalance to newBalance.
7. Using a 'FOR' loop, create and display the balance for each year.
8. newBalance= newBalance* INTEREST_RATE;
9. Review the FOR loop example in Chapter 7 -Section 7.5 page 114
10. Format the displayed balance to show 2 decimal places only.

Example:

Number of years to invest:5

Amount to Invest:1000

Year 1 balance =  1050.00
Year 2 balance =  1102.50
Year 3 balance =  1157.63
Year 4 balance =  1215.51
Year 5 balance =  1276.28

also
   Display the message "You have doubled your investment" and terminate the loop if/when you have more than doubled your initial investment. It is understood that the number of years to invest must be high enough to trigger this event.

Answer 1

code:

import java.util.*;                               //util package for scanner class
import java.text.DecimalFormat;                   //DecimalFormat class for rounding the balance to two decimals
public class CompoundInterest
{
   public static void main(String args[])               //main function
       {
       Scanner input=new Scanner(System.in);                   //scanner class for input taking purpose
       DecimalFormat decimal = new DecimalFormat("##.00");           //decimal object for rounding to two decimal values
       double CurrentBalance,NewBalance;                               //currentbalance and newbalance variables declaration
       final double INTEREST_RATE=1.05;                       //final double interest_rate variable
       int yearCount;
       System.out.println("Number of years to invest");           //asking user to enter the number of years to invest
       yearCount=input.nextInt();
       System.out.println("Amount to invest");                       //enter the amount to invest
       CurrentBalance=input.nextDouble();
       NewBalance=CurrentBalance;                           //assigning current balance to new balance
       for (int i=0;i<yearCount;i++)                   //iterating loop for every year
           {
           NewBalance=NewBalance*INTEREST_RATE;               //calculating new balance from given formula
           System.out.println("Year " + (i+1) +" balance = " + decimal.format(NewBalance));       //printing the new balance value of every year
           if (NewBalance>2*CurrentBalance)                       // if the new balance exceeds double of original investement
               {
               System.out.println("You have doubled your investment");       //print the statement and break the loop
               break;
               }
           }
       }
}

code screenshots and output:

Note : if you have any queries please post a comment thanks a lot......