Assignment #107 and Baby Calculator

Code

    /// Name: Brendan Baird
    /// Period: 6
    /// Program Name: Baby Calculator
    /// File Name: BabyCalculator.java
    /// Date Finished: 1/29/2016
    
    import java.util.Scanner;

    public class BabyCalculator
    {
    	public static void main( String[] args )
    	{
    		Scanner keyboard = new Scanner(System.in);
    
    		double a, b, c;
    		String op;
    
    		do
    		{
    			System.out.print("> ");
    			a  = keyboard.nextDouble();
    			op = keyboard.next();
    			b  = keyboard.nextDouble();
    
    			if ( op.equals("+") )
    				c = a + b;
                else if ( op.equals("-") )
                    c = a - b;
                else if ( op.equals("*") )
                    c = a * b;
                else if ( op.equals("/") )
                    c = a / b;
    			else
    			{
    				System.out.println("Undefined operator: '" + op + "'.");
    				c = 0;
    			}
    
    			if ( a != 0 )
                    System.out.println(c);
    
    		} while ( a != 0 );
            System.out.println("Goodbye");
    	}
    }
    

Picture of the output