//  File:  ParamPasser.java

//  In Java, all parameters are passed by value.  

//  This program shows that the primitive types are passed by value.
//  Two ints are passed to a method that tries - unsuccessfully -
//  to "swap" them.

public class ParamPasser 
{
	public void trySwap(int first, int second) 
	{
		int temp = first ;
		first = second ;
		second = temp ;
		
		System.out.println("\nIn method trySwap, after swapping:  " +
		                   "first = " + first + ", second = " + second) ;
	}
	
	public static void main(String args[]) 
	{
		// declare and initialize 2 "local" vars
		
		int first = 37 ;
		int second = 73 ;
		
		// print initial values
		
		System.out.println("Initial values of ints:  first = " + first +
		                   ", second = " + second) ;
		                   
		ParamPasser demo = new ParamPasser() ;
		
		// attempt a swap
		
		demo.trySwap(first, second) ;
		
		// print values after swap attempt
		
		System.out.println("\nAfter return from method trySwap:  " +
		                   "first = " + first + ", second = " + second) ;
	}	                   
}
 
 
/*  Program output:
                
Initial values of ints:  first = 37, second = 73

In method trySwap, after swapping:  first = 73, second = 37

After return from method trySwap:  first = 37, second = 73

*/