#include<stdio.h>
#define SIZE 100
    int stack[SIZE];
    int top= -1;
    void PUSH(int x){
        if(isFull(stack)){
            printf("Stack overflow %d\n",x);
        }
        else{
            top++;
            stack[top] = x;
            printf("%d",x);
            
        }
    }
    void POP(){
        if(isEmpty()){
            printf("Stack Underflow");
        }
        else{
            printf("%d\n",stack[top]);
            top--;
        }
    }
    void PEEK(){
        if(isEmpty()){
            printf("Stack is empty\n");
        }
        else{
            printf("top %d\n",stack[top]);
        }
    }
    void DISPLAY(){
        if(isEmpty()){
            printf("Stack is empty \n");
        }
        else{
            for(int i = top;i>=0;i--){
            printf("%d\n",top[i]);
        }
    }
    int main(){
    int values;
    void PUSH();
    int DISPLAY();
    int POP();
    int PEEK();
    int isFull();
    int isEmpty();
    PUSH(10);
    PUSH(20);
    display();
    POP();
    PEEK();
    }