Stack implementation in C

stack.c

#include<stdio.h>
#include<stdlib.h>
#define INT_MIN -99999999

struct stack{
    int top;
    unsigned int capacity;
    int * arr;
};

struct stack *createStack(unsigned int capacity){
    struct stack *stack = (struct stack*)malloc(sizeof(struct stack));
    stack->capacity = capacity;
    stack->top = -1;
    stack->arr = (int*)malloc(capacity*sizeof(int));
    return stack;
}

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->arr[++s->top] = data;
    printf("The item %d pushed to stack\n", data);
}

int pop(struct stack *s){
    if(isEmpty(s))
    return INT_MIN;
    return s->arr[s->top--];
}

int peek(struct stack *s){
    if(isEmpty(s))
    return INT_MIN;
    return s->arr[s->top];
}

int main()
{   
    int capacity = 100;
    struct stack *s = createStack(capacity);
    push(s, 10);
    push(s, 20);
    push(s, 30);
    printf("The peek of stack: %d\n", peek(s));
    pop(s);
    printf("The peek of stack: %d\n", peek(s));
}