stacks_using_arrays

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
struct stack{
    int top;
    unsigned capacity;
    int *array
};
struct stack* create_stack(unsigned capacity);
int isfull(struct stack* s);
int isempty(struct stack* s);
void push(struct stack* s,int data);
int pop(struct stack* s);
int main()
{
    struct Stack* stack = create_stack(100);
 
    push(stack, 10);
    push(stack, 20);
    push(stack, 30);
 
    printf("%d popped from stack\n", pop(stack));
 
    return 0;
}
struct stack* create_stack(unsigned capacity)
{
    struct stack* s= (struct stack*) calloc(1,sizeof(struct stack));
    s->top=-1;
    s->capacity=capacity;
    s->array= (int*) calloc(capacity,sizeof(struct stack));
    return s;
}
int isfull(struct stack* s)
{
    return (s->top==s->capacity-1);
}
int isempty(struct stack* s)
{
    return (s->top==-1);
}
void push(struct stack* s,int data)
{
    if (isfull(s))
        return ;
    s->top=s->top+1;
    s->array[s->top]=data;
        
}
int pop(struct stack* s)
{
    if (isempty(s))
        return NULL;
    return (s->array[s->top--]);
}