typedef int ElementType;
/* START: fig3_39.txt */
        #ifndef _Stack_h
        #define _Stack_h

        struct Node;
        typedef struct Node *PtrToNode;
        typedef PtrToNode Stack;

        int IsEmpty( Stack S );
        Stack CreateStack( void );
        void DisposeStack( Stack S );
        void MakeEmpty( Stack S );
        void Push( ElementType X, Stack S );
        ElementType Top( Stack S );
        void Pop( Stack S );

        #endif  /* _Stack_h */

/* END */