// Review Program
//
class Alteration
{
  void zero ( int x )
  {
    x = 0;
  }
}

class AlterTest
{
  public static void main ( String[] args )
  {
    Alteration alt = new Alteration();
    int value = 27;
    System.out.println( "Before:" + value );
    
    alt.zero( value );
    System.out.println( "After:"  + value );
  }
}

1. The program starts running with the static main() method.
2. An Alteration object is constructed.
   • The default constructor is used, since the class Alteration did not define a constructor.
   • The Alteration object contains the zero() method.
3. The primitive int variable value is initialized to 27.
4. The number currently held in value is printed out.
   • Before: 27 is printed
5. The zero() method is called with value as a parameter.
   • The number held in value (27) is copied to the formal parameter x.
   • The zero() method changes x to zero.
   • Control returns to the caller; value has not been altered.
6. The number currently held in value is printed out.
   • After: 27 is printed.