app stack

#include <stdio.h>
#define MAX 100

int stack[MAX];
int top = -1;

// Check if stack is empty
int isEmpty() {
    return top == -1;
}

// Check if stack is full
int isFull() {
    return top == MAX - 1;
}

// Push element onto stack
void push(int x) {
    if (isFull()) {
        printf("Stack Overflow\n");
        return;
    }
    stack[++top] = x;
    printf("Pushed %d\n", x);
}

// Pop element from stack
int pop() {
    if (isEmpty()) {
        printf("Stack Underflow\n");
        return -1;
    }
    return stack[top--];
}

// Peek top element
int peek() {
    if (isEmpty()) {
        printf("Stack is empty\n");
        return -1;
    }
    return stack[top];
}

int main() {
    push(10);
    push(20);
    push(30);

    printf("Top element is %d\n", peek());

    printf("Popped element is %d\n", pop());
    printf("Popped element is %d\n", pop());

    if (isEmpty())
        printf("Stack is empty\n");
    else
        printf("Stack is not empty\n");

    return 0;
}