/**
  * Swaps the values of two variables.
  * The first group of statement are incorrect.
  * The second group is the proper way to swap.
  *
  *@Author Anthony Larrain
  *@Version 1 Summer 2000
  */
  class Variable3{	  
	  public static void main(String [] args){
		  int first  = 10;
		  int second = 20;
		  
		  // output variables
		  System.out.println("First  is:\t" + first);
		  System.out.println("Second is:\t" + second);
		  
		  // 1
		  first = second;
		  second = first;
		  System.out.println(); // blank line
		  System.out.println("First attempt to swap");
		  System.out.println("First  is:\t" + first);
		  System.out.println("Second is:\t" + second);
		  
		  // reset the variable first back to the original value
		  first = 10;
		  // 2
		  // need a third variable to swap
		  int temp = first;
		  // now we can replace first because we have a copy of it.
		  first = second;
		  // need to give second the value initially in first
		  second = temp;
		  
		  // output
		  System.out.println(); // blank line
		  System.out.println("Second attempt to swap");
		  System.out.println("First  is:\t" + first);
		  System.out.println("Second is:\t" + second);
	  }
  }
  
  /* Notes:
   * \t  implies a tab space
   * the statement  first = second; take the value in the variable second
   * and copy it into the variable identitified by first. No change occurs
   * to second
   */