#ifndef _COIN_H
#define _COIN_H

// Coin Class
//
// Author:  Alyce Brady
//
// Creation Date:  1/13/2000
//
// Coin objects simulate a coin that, when tossed, has an
// equal probability of turning up heads or tails.  When the
// coin is first constructed, both the Heads and Tails functions
// will return false.  Once the Toss function has been called
// for the first time, however, either Heads or Tails (but not
// both) will always be true.  Between calls to the Toss function,
// the Heads and Tails functions can be called as often as desired
// and will always return the same true/false value (in other words,
// to change whether the coin is showing heads or tails is to toss
// the coin).
//
// By default, a Coin object will produce a different series of
// numbers (through repeated calls to the Toss method) every time the
// program is run.  When testing, though, it is often useful to have a
// program generate the same sequence of numbers each time it is run;
// this can be achieved by specifying a "seed" when the first Coin
// object in the program is created.
// 
//
// Technical Note:
//   The Coin class makes use of the RandGen class to generate random
//   numbers.  The "seed" used by all random number generation in a
//   program is set the first time a random number generator object is
//   constructed by the program.  All other random number generator
//   objects created later in the program will use the same seed.

#include "randgen.h"

class Coin
{
  public:

    // Constructors
      // The default Coin constructor constructs a default RandGen
      // object; the second Coin constructor constructs a RandGen
      // object with a seed.
      //
      // If the first RandGen object in a program is constructed with
      // the default constructor, a different series of numbers is
      // produced every time the program is run.  If the first RandGen
      // object is constructed with a seed, the same series of numbers
      // is produced every time.

    Coin();                 // default constructor
    Coin(int seed);         // produce same series every time
                            //   (most useful during testing)    

    // Accessing functions

    bool Heads();
		// precondition: coin has been tossed at least once
		// postcondition: returns true if last toss turned up heads

    bool Tails();
		// precondition: coin has been tossed at least once
		// postcondition: returns true if last toss turned up tails

    // Modifying functions 

    void Toss();
		// postcondition: 50/50 chance that Heads is true

  private:
    RandGen  randNumGen;        // the random number generator
    bool     tossed;            // false until first call to Toss; 
                                //       true from then on
    bool     showingHeads;      // true if the coin is showing heads
};

#endif    // _COIN_H not defined