Question

CIT 149 JAVA 1 programming question?

There will be two files for this problem. The first one, called FutureValue will hold the main method. The second file called FinancialUtils will hold the two methods that will display what the program will do, and perform the calculations. In the main method, which controls the logic of the program, you will first call the displayInstructions method which will display a statement of what the program will do. You will write this description in the displayInstructions method. Then the user will be prompted within the main method to input the monthly investment, the number of months of the investment, and the annual interest rate. You will be asking the user for the annual interest rate as a decimal (like 0.03), however, you will be calculating the monthly interest rate by dividing that annual rate by 12 (number of months in a year). That calculation will take place in the main method, prior to sending the monthly interest rate to the static method that will do the future value calculation. The name of the static method that will display the instructions, will be called displayInstructions. The name of the static method that will return the future value of the investment, will be called calculateFutureValue. The first static method will be a void method. It will not return any value. It will simply display the instructions using the familiar System.out.println(). The second static method will be passed (from the main method) the amount of monthly investment (the same for every month), the monthly interest rate (calculated from the annual interest rate annual interest rate divided by 12, in the main method), and the number of months of the monthly investments will be made. This static method will return the futureValue to the main method. You will need to have a variable set up in the main method to receive that returned value. See the Static Method Practice C4PE sheet for how that is done. The calculation of the future value will take place in a for loop where the counter (use i) will start at 1 and loop for the number of months passed to the method. Each time through the loop, you will use the following calculation: futureValue = (futureValue + monthlyInvestment) * (1 + monthlyInterestRate); Notice that the variable futureValue is used on both sides of the equal sign. The is so that futureValue is added to the amount previously calculated in the prior loop each time. So this acts as an accumulator and calculates the new month’s interest on the new total. Look at that expression carefully, and make sure you understand how it works. Test your program with several numbers to ensure that it performs as it should.

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// FutureValue.java

import java.util.Scanner;

public class FutureValue {

      public static void main(String[] args) {

            // scanner to read user input

            Scanner scanner = new Scanner(System.in);

            // displaying instructions

            FinancialUtils.displayInstructions();

            // asking and receiving inputs

            System.out.print("\nEnter monthly investment: ");

            double amount = scanner.nextDouble();

            System.out.print("Enter annual interest rate: ");

            double annualIntRate = scanner.nextDouble();

            System.out.print("Enter number of months: ");

            int months = scanner.nextInt();

            // finding monthly interest rate

            double monthlyIntRate = annualIntRate / 12.0;

            // calculating future value

            double futureValue = FinancialUtils.calculateFutureValue(amount,

                        monthlyIntRate, months);

            // displaying it with a precision of two digits after decimal point

            System.out.printf("\nThe future value will be $%.2f", futureValue);

      }

}

// FinancialUtils.java

public class FinancialUtils {

      // method to display the instructions

      public static void displayInstructions() {

            System.out

                        .println("==============================================================="

                                    + "\nThis program calculates the future value of an investment\n"

                                    + "given the monthly investment, annual interest rate (in decimal)\nand "

                                    + "number of months\n"

                                    + "===============================================================");

      }

      // method to calculate and return the future value, given monthly

      // investment, monthly interest rate and number of months

      public static double calculateFutureValue(double monthlyInvestment,

                  double monthlyInterestRate, int numMonths) {

            double futureValue = 0;

            // using a for loop, calculating the future value using the equation

            // provided in the question

            for (int i = 1; i <= numMonths; i++) {

                  futureValue = (futureValue + monthlyInvestment)

                              * (1 + monthlyInterestRate);

            }

            // returning final value

            return futureValue;

      }

}

/*OUTPUT*/

===============================================================

This program calculates the future value of an investment

given the monthly investment, annual interest rate (in decimal)

and number of months

===============================================================

Enter monthly investment: 1250

Enter annual interest rate: 0.075

Enter number of months: 24

The future value will be $32460.02