#include<stdio.h>
#define MAX 100
int stack[MAX];
int top=-1;
void push(int x)
{
    if(top==MAX-1)
    {
        printf("Stack overflow\n");
    }
    else
      stack[++top]=x;
}
void peek(){
    if(top==-1)
    {
        printf("Stack is empty\n");
    }
    else
    {
        printf("%d\n",stack[top]);
    }
}
int main()
    push(10);
    push(20);
    peek();
    push(30);
    peek();
    return 0;
}