Calculates the Greatest Common Divisor of two numbers passed into the program through command line arguments. : Math « Development Class « Java






Calculates the Greatest Common Divisor of two numbers passed into the program through command line arguments.

        
//package numeric;

/**
* This class calculates the Greatest Common
* Divisor of two numbers passed into the program
* through command line arguments.
*
* @author Alex Laird
* @version 1.0
* File: GCD.java
* Created: Sep 2008
*/
public class GCD
{
     /**
     * Returns the Greatest Common Divisor of two
     * numbers that are passed into the method.
     *
     * @param a the first integer for comparison.
     * @param b the second integer for comparison.
     * @throws NegativeNumberException if the input given is negative.
     * @returns the Greatest Common Divisor.
     */
     public static int gcd(int a, int b) throws Exception
     {
         // throw an exception if the input is negative
         if(a < 0 || b < 0)
         {
             throw new Exception("The user has entered a "
                                               + "negative number.");
         }

          if(b == 0)
               return a;
          else
               return gcd(b, a % b);
     }

     /**
     * The main method from which the program executes;
     * it handles all I/O and method execution.
     *
     * @param args Arguments received from the command line (two numbers).
     * @param gcd The calcuated Greatest Common Divisor of args[0] and args [1].
     */
     public static void main(String[] args)
     {
          // ensure the user only enters two arguments
          if(args.length == 2)
          {
               // ensure the users arguments are numbers
               try
               {
                    // calculate gcd
                    int gcd = gcd(Integer.parseInt(args[0]),
                              Integer.parseInt(args[1]));

                    System.out.println("The Greatest Common Divisor of "
                                       + args[0] + " and " + args[1] + " is "
                                       + gcd + ".");
               }
               catch(NumberFormatException c)
               {
                    System.out.println("Your arguments must be in "
                                       + "the form of integers when "
                                       + "running the program (ex. "
                                       + "enter 'java numeric.GCD "
                                       + "50 30').");
               }
               catch(Exception c)
               {
                    // used only in GUI
               }

          }
          else
          {
               System.out.println("Enter two numbers as arguments "
                                  + "when running the program (ex. "
                                  + "enter 'java numeric.GCD 50 30').");
          }
     }
}

   
    
    
    
    
    
    
    
  








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