Project 4; Calculator

Code

// Donovan Rich
// Project: Calculator
// Calculator.java
// 4/21/2016

import java.util.Scanner;

public class Calculator
{
    public static void main( String[] args )
    {
        Scanner keyboard = new Scanner(System.in);
        double input = 0;
        String op="";
        do
        {
            System.out.print("\n> ");
            input = keyboard.nextDouble();
            System.out.print(" ");
            op = keyboard.next();
            if ( op.equals("+") )
            {
                addition(input);
            }
            else if ( op.equals("-") )
            {
                subtraction(input);
            }
            else if ( op.equals("*") )
            {
                multiplication(input);
            }
            else if ( op.equals("/") )
            {
                division(input);
            }
            else if ( input == 0 || op.equals("0") )
            {
                System.out.println("Thanks for using CalTek!");
                input = 0;
            }
            else
            {
                System.out.println("ERROR. Operator unsupported. Please try again.");
            }
        } while ( input != 0 );
    }
    
    public static void addition(double input)
    {
        Scanner keyboard = new Scanner(System.in);
        System.out.print(" ");
        double inter = keyboard.nextInt(), eq = input+inter;
        System.out.print(" = " + eq );
    }
    public static void subtraction(double input)
    {
        Scanner keyboard = new Scanner(System.in);
        System.out.print(" ");
        double inter = keyboard.nextInt(), eq = input-inter;
        System.out.print(" = " + eq ); 
    }
    public static void multiplication(double input)
    {
        Scanner keyboard = new Scanner(System.in);
        System.out.print(" ");
        double inter = keyboard.nextInt(), eq = input*inter;
        System.out.print(" = " + eq ); 
    }
    public static void division(double input)
    {
        Scanner keyboard = new Scanner(System.in);
        System.out.print(" ");
        double inter = keyboard.nextInt(), eq = input/inter;
        System.out.print(" = " + eq ); 
    }
}


        

Picture of the output