stack implementation in c

1#include <stdio.h>
2
3int MAXSIZE = 8;       
4int stack[8];     
5int top = -1;            
6
7int isempty() {
8
9   if(top == -1)
10      return 1;
11   else
12      return 0;
13}
14   
15int isfull() {
16
17   if(top == MAXSIZE)
18      return 1;
19   else
20      return 0;
21}
22
23int peek() {
24   return stack[top];
25}
26
27int pop() {
28   int data;
29	
30   if(!isempty()) {
31      data = stack[top];
32      top = top - 1;   
33      return data;
34   } else {
35      printf("Could not retrieve data, Stack is empty.\n");
36   }
37}
38
39int push(int data) {
40
41   if(!isfull()) {
42      top = top + 1;   
43      stack[top] = data;
44   } else {
45      printf("Could not insert data, Stack is full.\n");
46   }
47}
48
49int main() {
50   // push items on to the stack 
51   push(3);
52   push(5);
53   push(9);
54   push(1);
55   push(12);
56   push(15);
57
58   printf("Element at top of the stack: %d\n" ,peek());
59   printf("Elements: \n");
60
61   // print stack data 
62   while(!isempty()) {
63      int data = pop();
64      printf("%d\n",data);
65   }
66
67   printf("Stack full: %s\n" , isfull()?"true":"false");
68   printf("Stack empty: %s\n" , isempty()?"true":"false");
69   
70   return 0;
71}

1typedef struct Nodo{
2   Elem val;
3   struct Nodo *next;
4} *Stack;
5Stack Empty(){return NULL;}
6bool IsEmpty(Stack a){return a==NULL;}
7Elem Top(Stack a){return a->val;} 
8Stack Pop(Stack l){return l->next;}
9Stack Push(Elem x,Stack res){
10    Stack nuevo=(Stack)malloc(sizeof(struct Nodo));
11    nuevo->val=x;
12    nuevo->next=res;
13    return nuevo;
14}