/**
 * Matt Kretchmar
 * February 28, 2006
 * Calc.java
 * This program implements a simple command-line calculator.
 * It supports A op B where A,B are floating point operands
 * and "op" is +, -, *, /, ^.  
 */

class Calc1
{
    public static void main ( String [] args )
    {
        double operand1 = 0;
        double operand2 = 0; 
        double result = 0;
        
        // wrong number of arguments?
        if ( args.length != 3 )
        {
            System.out.println("Wrong number of arguments.  Expects:");
            System.out.println("Calc A op B");
            System.exit(1);
        }
        
        // first and third not valid doubles?
        try
        {
            operand1 = Double.parseDouble(args[0]);
        }
        catch ( NumberFormatException nfe)
        {
            System.out.println("Invalid numeric format for operand A.  Expects:");
            System.out.println("Calc A op B");
            System.exit(1);
        }

        try
        {
            operand2 = Double.parseDouble(args[2]);
        }
        catch ( NumberFormatException nfe)
        {
            System.out.println("Invalid numeric format for operand B.  Expects:");
            System.out.println("Calc A op B");
            System.exit(1);
        }
        
        // Attempt operation
        if ( args[1].equals("+") )
            result = operand1 + operand2;
        else if ( args[1].equals("-") )
            result = operand1 + operand2;
        else if ( args[1].equals("*") )
            result = operand1 * operand2;
        else if ( args[1].equals("/") )
            result = operand1 / operand2;
        else if ( args[1].equals("^") )
            result = Math.pow(operand1,operand2);
        else
        {
            System.out.println("Invalid op (+,-,*,/,^).  Expects:");
            System.out.println("Calc A op B");
            System.exit(1);
        }
        
        System.out.println(result);
    }
}