//----------------------------------------------------------------------
//  SPECIFICATION FILE (cstack.h)
//  This module exports an ADT for a stack of characters.
//----------------------------------------------------------------------
#ifndef cstack_h
#define cstack_h 1
#include "bool.h"

const int SMAX_LENG = 100;

class CharStack {

    // ABSTRACTLY: a sequence of component values of type char

public:
    CharStack();
        // MODIFIES: self
        // POST: the sequence is empty

    Boolean IsEmpty() const;
        // POST: FCTVAL == (sequence is empty)

    Boolean IsFull() const;
        // POST: FCTVAL == true if no more
        // items can be stored, false otherwise

    void Push(char newItem );
        // PRE: the sequence isn't full
        // MODIFIES: self
        // POST: newItem is the first in the sequence, rest is self<entry> 

    char Top() const;
        // PRE: the sequence isn't empty
        // POST: FCTVAL == first item in the sequence

    void Pop();
        // PRE: the sequence isn't empty
        // MODIFIES: self
        // POST: the sequence is the tail of the sequence in self<entry>

#include "cstack.pri"
};
#endif