Create CompoundInterest.java

Author: Thesnowmanndev

Starting out with Java (Tony Gaddis) 7th Ed/Programming Challenges/2. Chapter 2 - Java Fundamentals/21. Compound Interest/src/CompoundInterest.java

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+import java.text.DecimalFormat;
+import java.util.Scanner;
+
+public class CompoundInterest {
+/*
+    When a bank account pays compound interest, it pays interest not only on the principal amount that was deposited
+    into the account, but also on the interest that has accumulated over time. Suppose you want to deposit some money
+    into a savings account, and let the account earn compound interest for a certain number of years. The formula for
+    calculating the balance of the account after a specified number of years is:
+
+    A=P(1+rn)nt
+
+    The terms in the formula are:
+
+    A is the amount of money in the account after the specified number of years.
+    P is the principal amount that was originally deposited into the account.
+    r is the annual interest rate.
+    n is the number of times per year that the interest is compounded.
+    t is the specified number of years.
+
+    Write a program that makes the calculation for you. The program should ask the user to input the following:
+
+    - The amount of principal originally deposited into the account
+    - The annual interest rate paid by the account
+    - The number of times per year that the interest is compounded
+        (For example, if interest is compounded monthly, enter 12. If interest is compounded quarterly, enter 4.)
+    - The number of years the account will be left to earn interest
+
+    Once the input data has been entered, the program should calculate and display the amount of money that will be in
+    the account after the specified number of years.
+
+    Note: The user should enter the interest rate as a percentage. For example, 2 percent would be entered as 2,
+    not as .02. The program will then have to divide the input by 100 to move the decimal point to the correct position.
+*/
+    private double principalAmount;
+    private double annualInterestRate;
+    private double numberOfCompoundedTimes;
+    private double numberOfYears;
+
+    private static final Scanner input = new Scanner(System.in);
+    private static final DecimalFormat format = new DecimalFormat("#,###.##");
+
+    public double calculateCompoundInterest() {
+        double A;
+        double P = getPrincipalAmount();
+        double r = getAnnualInterestRate() / 100;
+        double n = getNumberOfCompoundedTimes();
+        double t = getNumberOfYears();
+
+        A = P * (1 + r * n) * n * t;
+
+        return A;
+    }
+
+    public double getNumberOfYears() {
+        return numberOfYears;
+    }
+
+    public double getNumberOfCompoundedTimes() {
+        return numberOfCompoundedTimes;
+    }
+
+    public double getAnnualInterestRate() {
+        return annualInterestRate;
+    }
+
+    public double getPrincipalAmount() {
+        return principalAmount;
+    }
+
+    public void setPrincipalAmount(double inputPrincipalAmount) {
+        principalAmount = inputPrincipalAmount;
+    }
+
+    public void setAnnualInterestRate(double inputAnnualInterestRate) {
+        annualInterestRate = inputAnnualInterestRate;
+    }
+
+    public void setNumberOfCompoundedTimes(double inputNumberOfCTimes) {
+        numberOfCompoundedTimes = inputNumberOfCTimes;
+    }
+
+    public void setNumberOfYears(double inputNumberOfYears) {
+        numberOfYears = inputNumberOfYears;
+    }
+
+    public static void main(String[] args) {
+        CompoundInterest compoundInterest = new CompoundInterest();
+
+        System.out.println( "Input the amount of principal originally deposited into the account. Ex. 10000");
+        compoundInterest.setPrincipalAmount(input.nextDouble());
+
+        System.out.println( "Input the annual interest rate paid by the account. Ex. 2 for 2%");
+        compoundInterest.setAnnualInterestRate(input.nextDouble());
+
+        System.out.println( "Input the number of times per year that the interest is compounded. Monthly = 12. " +
+                            "Quarterly = 4.");
+        compoundInterest.setNumberOfCompoundedTimes(input.nextDouble());
+
+        System.out.println( "Input the number of years the account will be left to earn interest. Ex. 35 for 35 years");
+        compoundInterest.setNumberOfYears(input.nextDouble());
+
+        double estimatedAmount = compoundInterest.calculateCompoundInterest();
+
+        System.out.println( "In " + compoundInterest.getNumberOfYears() + " years you will have a estimated " +
+                            "account balance of $" + format.format(estimatedAmount) + ".");
+    }
+}