typedef struct t_stack *stack;

stack ConsStack( int max_items, int item_size );
/* Construct a new stack
   Pre-condition: (max_items > 0) && (item_size > 0)
   Post-condition: returns a pointer to an empty stack
*/

void Push( stack s, void *item );
/* Push an item onto a stack
   Pre-condition: (s is a stack created by a call to ConsStack) &&
                  (existing item count < max_items) &&
                  (item != NULL)
   Post-condition: item has been added to the top of s
*/

void *Pop( stack s );
/* Pop an item of a stack
   Pre-condition: (s is a stack created by a call to 
                  ConsStack) &&
                  (existing item count >= 1)
   Post-condition: top item has been removed from s
*/

#include<stdio.h>
#include "mystack.h"

void push(Stack *S, float val)
{
    S->v[ S->top ] = val; 
   (S->top)++;    
/*  Equivalent to: S->v[ (S->top)++ ] = val;   */
}

float pop(Stack *S)
{
    (S->top)--;
    return (S->v[S->top]);
/*  Equivalent to: return (S->v[--(S->top)]);  */
}

void init(Stack *S)
{
    S->top = 0;
}

int full(Stack *S)
{
    return (S->top >= 20);
}

void MyStackPrint(Stack *S)
{
    int i;
    if (S->top == 0)
       printf("Stack is empty.\n");
    else
    {
       printf("Stack contents: ");
       for (i=0;i<S->top;i++)
       {
          printf("%g  ",S->v[i]); 
       }
       printf("\n");
    }
}