/* * File: stack.h * ------------- * This interface defines an abstraction for stacks. In any * single application that uses this interface, the values in * the stack are constrained to a single type, although it * is easy to change that type by changing the definition of * stackElementT in this interface. */
#ifndef _stack_h#define _stack_h
#include "genlib.h"
/* * Type: stackElementT * ------------------- * The type stackElementT is used in this interface to indicate * the type of values that can be stored in the stack. Here the * stack is used to store values of type double, but that can * be changed by editing this definition line. */
typedef double stackElementT;
/* * Type: stackADT * -------------- * The type stackADT represents the abstract typed used to store * the elements that have been pushed. Because stackADT is * defined only as a pointer to a concrete structure that is not * itself defined in the interface, clients have no access to * the underlying fields. */
typedef struct stackCDT *stackADT;
/* * Function: NewStack * Usage: stack = NewStack(); * -------------------------- * This function allocates and returns a new stack, which is * initially empty. */
stackADT NewStack(void);
/* * Function: FreeStack * Usage: FreeStack(stack); * ------------------------ * This function free the storage associated with the stack. */
void FreeStack(stackADT stack);
/* * Function: Push * Usage: Push(stack, element); * ---------------------------- * This function pushes the specified element onto the stack; */void Push(stackADT stack, stackElementT element);

/* * Function: Pop * Usage: element = Pop(stack); * ----------------------------- * This function pops the top element from the stack and returns * that value. The first value popped is always the last one * that was pushed. If the stack is empty when Pop is called, * the function calls Error with an appropriate message. */
stackElementT Pop(stackADT stack);

/* * Function: StackIsEmpty, StackIsFull * Usage: if (StackIsEmpty(stack)) ... *        if (StackIsFull(stack)) ... * --------------------------------------- * This function test whether the stack is empty or full. */
bool StackIsEmpty(stackADT stack);bool StackIsFull(stackADT stack);
/* * Function: StackDepth * Usage: depth = StackDepth(stack); * --------------------------------- * This function returns the number of elements currently pushed * on the stack. */int StackDepth(stackADT stack);

/* * Function: GetStackElement * Usage: element = GetStackElement(stack, index); * ----------------------------------------------- * This function returns the element at the specified index in * the stack, where the top of the stack is defined as index 0. * For example, calling GetStackElement(stack, 0) returns the top * element on the stack without removing it. If the caller tries * to select an out-of-range element, GetStackElement calls Error. * Note: This function is not a fundamental stack operation and * is instead provided principally to facilitate debugging. */stackElementT  GetStackElement(stackADT stack, int index);
#endif