Calculator.java Source code

Introduction

Here is the source code for Calculator.java

Source

import java.util.Scanner;

public class Calculator {
    public static void main(String[] args) {
        System.out.println("type something like: 1+3");
        Scanner scanner = new Scanner(System.in);
        double n1 = Double.NaN;
        double n2 = Double.NaN;
        String operation = null;

        try {
            n1 = scanner.nextDouble();
            operation = scanner.next();
            n2 = scanner.nextDouble();
            double result = calculate(n1, n2, operation);
            System.out.printf("%s %s  %s  = %.2f%n", n1, operation, n2, result);
        }

        catch (Exception e) {
            System.out.println("An invalid expression.");
        }
    }

    public static double calculate(double op1, double op2, String operation) {
        switch (operation) {
        case "+":
            return op1 + op2;
        case "-":
            return op1 - op2;
        case "*":
            return op1 * op2;
        case "/":
            return op1 / op2;
        }

        return Double.NaN;
    }
}