/** 
 Program: 	EssentialFlow
 Purpose: 	simple demonstration of Java control flow
 @author 	john@december.com 
 @version	1.05; 21 Nov 95 
 Note:          updated to 1.00 beta 
 Changes:       Quick version of if-then branching won't compile in beta  
 Output:        
	BRANCHING
	OK.
	This is
	remaining OK.
	Human body.
	LOOPING
	Hi up: 1
	Hi up: 2
	Hi down: 3
	Hi down: 2
	Hi down: 1
	Hi again: -50
	Hi again: 0
	Hi again: 50
	Still OK: 0
	Still OK: 1
	Still OK: 2
	OK = true counter = 500
 */

class EssentialFlow{
   public static void main (String args[]) {
      
      System.out.println("BRANCHING");
      // If-then branching. 

      boolean OK = true;

      if (OK) 
         System.out.println("OK.");
      else
         System.out.println("NOT OK.");

      // Quick version of if-then branching. 
      // won't compile under beta
      // OK ? System.out.println("Quick OK.") : 
      //      System.out.println("Quick NOT OK.");

      // Mutiple line if-then branches. 

      if (OK) {
         System.out.println("This is");
         System.out.println("remaining OK.");
         }
      else {
         System.out.println("Or is it");
         System.out.println("NOT OK?");
         }

      // SWITCH type branching

      int temperature = 37;
      switch (temperature){
         case (0): 
            System.out.println("Freezing water!");
            break;
         case (37): 
            System.out.println("Human body.");
            break;
         case (100): 
            System.out.println("Boiling water!");
            break;
         default: 
            System.out.println("Some temperature.");
      }

      System.out.println("LOOPING");

      // Simple FOR loop up. 
      int counter;

      for (counter = 1; counter < 3; counter++){
         System.out.println("Hi up: " + counter);
         }; 

      // Simple FOR loop down. 
      for (counter = 3; counter > 0; counter--){
         System.out.println("Hi down: " + counter);
         }; 

      // FOR loop with non ++ step size expression.  
      for (counter = -50; 
           counter < 99; 
           counter = counter + 50){
         System.out.println("Hi again: " + counter);
         }

      // While loop with condition checked at the start

      counter = 0;
      OK = true;

      while (OK) {
         System.out.println("Still OK: " + counter);
         counter++;
         OK = (counter < 3);
         }

      // do-while loop executes at least once; condition check at end

      counter = 500;
      OK = true;

      do { 
         System.out.println("OK = " + OK + " counter = " + counter);
         counter++;
         OK = (counter < 3);
      } while(OK);

   }
}