// A stack class is defined here with a private internal storage
// and public functions that can manipulate it.

// include this file in any program that needs a stack of characters
// After page 139 of C++ for Pascal Programmers by Ira Pohl

#define MAX_LEN	255
struct stack{
private:
	char	s[MAX_LEN];
	int top_at;
	const static int EMPTY=-1;
	const static int FULL= MAX_LEN-1;
public:

	void make_new(void) { top_at=EMPTY; }
	void push(char c) { top_at++;  s[top_at]=c; }
	char pop(void) { return ( s[top_at--]); }
	char top(void) { return (s[top_at]); }
	bool empty(void)	{ return (top_at==EMPTY); }
	bool full(void) { return (top_at== FULL); }

	stack(void){make_new();}  //auto initialization
	~stack(void){while(!empty())pop();}  // automatic destruction

};