Main.java

/**
 * Demo entry point showing basic usage of the Calculator class.
 */
public class Main {

    public static void main(String[] args) {
        Calculator calculator = new Calculator();

        double a = 12;
        double b = 4;

        System.out.println("Calculator Demo");
        System.out.println("a = " + a + ", b = " + b);
        System.out.println("a + b = " + calculator.add(a, b));
        System.out.println("a - b = " + calculator.subtract(a, b));
        System.out.println("a * b = " + calculator.multiply(a, b));
        System.out.println("a / b = " + calculator.divide(a, b));

        try {
            calculator.divide(a, 0);
        } catch (ArithmeticException e) {
            System.out.println("Error caught: " + e.getMessage());
        }
    }
}