/**********************************************************************************
*  Stack.h
*  Header file for Stack ADT
***********************************************************************************/
#if !defined(_STACK_H_INCLUDE_)
#define _STACK_H_INCLUDE_


/***************************** Exported Types *************************************/
typedef struct Stack * StackRef;


/************** Constructors-Destructors ******************************************/

/*
*  newStack
*  Returns StackRef pointing to new StackSturct which represents an empty Stack.
*  Initializes top field to NULL, sets height field to 0.  Exported.
*/
StackRef newStack(void);

/*
*  freeStack
*  Frees all heap memory associated with the StackRef *pS, including all memory
*  in existing Nodes.  Sets *pS to NULL.  Exported.
*/
void freeStack(StackRef* pS);


/***************** Access functions ***********************************************/

/*
*  getTop
*  Returns the value at the top of S.
*  Pre: !isEmpty(S)
*/
int getTop(StackRef S);

/*
*  getHeight
*  Returns the height of S
*/
int getHeight(StackRef S);

/*
*  isEmpty
*  Returns True if S is empty, otherwise returns false
*/
int isEmpty(StackRef S);


/****************************** Manipulation procedures ***************************/

/*
*  push
*  Places new data element on top of S
*  Post: !isEmpty(S)
*/
void push(StackRef S, int data);

/*
*  pop
*  Deletes element on top of S
*  Pre: !isEmpty(S)
*/
void pop(StackRef S);


/*************** Other Functions *************************************************/

/*
*  printStack
*  Prints data elements in S on a single line to stdout.
*/
void printStack(StackRef S);

/*
*  equals
*  returns true if Stack A is identical to Stack B, false otherwise
*/
int equals(StackRef A, StackRef B);


#endif