#include<stdio.h>
#include<stdlib.h>
#define SIZE 5
int x,i;
int values;
    void PUSH();
    void DISPLAY();
    void POP();
    void PEEK();
    int stack[SIZE];
    int top= -1;
    int isFull(){
        return (top==SIZE-1);
    }
    int isEmpty(){
        return (top==1);
    }
    void PUSH(int x){
        if(isFull()){
            printf("Stack overflow %d\n",x);
        }
        else{
            top++;
            stack[top] = x;
            printf("%d ",x);
            
        }
    }
    void POP(){
        if(isEmpty()){
            printf(" ");
        }
        else{
            printf("%d \n",stack[top]);
            top--;
        }
    }
    void PEEK(){
        if(isEmpty()){
            printf(" ");
        }
        else{
            printf("top %d\n",stack[top]);
        }
    }
    //int DISPLAY(){
       // if(isEmpty()){
           // printf("Stack is empty \n");
       // }
       // else{
           // for(int i = top;i>=0;i--){
            //printf("%d\n",top[i]);
        //}
    //}
    int main(){
    int isFull();
    int isEmpty();
    PUSH(10);
    PUSH(20);
    printf(10\n);
    //DISPLAY();
    POP;
    PEEK();
    }