// FILE: charstack.h 
// ________________________________________________________________________
//
// CONSTRUCTOR for the CharStack template class:
//   CharStack( )
//     Postcondition: The stack has been initialized as an empty stack.
//
// MODIFICATION MEMBER FUNCTIONS for the CharStack class:
//   void push(const char& entry)
//     Precondition: size( ) < CAPACITY.
//     Postcondition: A new copy of entry has been pushed onto the stack.
//
//   void pop( )
//     Precondition: size( ) > 0.
//     Postcondition: The top char of the stack has been removed.
//
// CONSTANT MEMBER FUNCTIONS for the CharStack class:
//   bool empty( ) const
//     Postcondition: Return value is true if the stack is empty.
//
//   size_type size( ) const
//     Postcondition: Return value is the total number of chars in the stack.
//
//   char top( )
//     Precondition: size( ) > 0.
//     Postcondition: The return value is the top char of the stack but the
//     stack is unchanged. 
//
//  VALUE SEMANTICS for the CharStack class:
//     Assignments and the copy constructor may be used with CharStack 
//     objects.

#ifndef CHARSTACK_H
#define CHARSTACK_H
#include <cstdlib> // Provides size_t

class CharStack
{
public:
	// TYPEDEFS AND MEMBER CONSTANT 
	typedef size_t size_type;
	typedef char value_type;
	enum { CAPACITY = 30 }; 
	// CONSTRUCTOR
	CharStack( ) { used = 0; }
	// MODIFICATION MEMBER FUNCTIONS
	void push(const char& entry);
	void pop( );
	// CONSTANT MEMBER FUNCTIONS
	bool empty( ) const { return (used == 0); }
	size_type size( ) const { return used; }
	char top( ) const;
private:
	char data[CAPACITY];        // Partially filled array 
	size_type used;             // How much of array is being used
};

#endif