Handling Exceptions and Debugging - Beginning Java Programming: The Object-Oriented Approach - page 193

appropriate. In other methods, it might be suitable to add the throws declaration and then handle
the exception (with a try/catch block) in the main or other method that calls this method.
In order to demonstrate how this works, consider the next example.
import java.text.DecimalFormat;
import java.util.InputMismatchException;
import java.util.Scanner;
public class ThrowsExceptions {
public static void main(String[] args) {
try {
// store the double[] returned by the scanValues() method
double[] userValues = scanValues();
// store the double returned by the calculatePayment() method
double payment = calculatePayment(userValues);
// create a decimal format with two places after the decimal point
DecimalFormat df = new DecimalFormat("0.##");
// print the calculated payment according to the format above
System.out.println("Monthly payment: $" + df.format(payment));
} catch (InputMismatchException ime) {
// scanValues() method throws InputMismatchException
// if user's entry cannot be parsed into a double
System.out.println("You must enter double values. "
+ "Please restart program.");
// terminate the program
System.exit(0);
} catch (ArithmeticException ae) {
// calculatePayment() method throws ArithmeticException
// if years == 0
System.out.println("Years must be greater than 0. "
+ "Please restart program.");
// terminate the program
System.exit(0);
} catch (IndexOutOfBoundsException ioob) {
// calculatePayment() method throws IndexOutOfBoundsException
// if double[] has less than 3 elements
System.out.println("Three doubles are required. "
+ "Please restart program.");
// terminate the program
System.exit(0);
}
}
// method asks for and scans three doubles:
// principle, interest rate, and loan years
public static double[] scanValues() throws InputMismatchException {
double[] values = new double[3];
try (Scanner scan = new Scanner(System.in)) {
System.out.print("Enter the loan amount: ");
values[0] = scan.nextDouble();