StacksUsingArrayList.java

import java.util.ArrayList;
public class StacksUsingArrayList {
    static class Stack{
        static ArrayList<Integer> list=new ArrayList<>();
        public static boolean isEmpty(){
            return list.size()==0;
        }
        public static void push(int data){
            list.add(data);
        }
        public static int pop(){
            if(isEmpty()){
                return -1;
            }
            int top=list.get(list.size()-1);p
            list.remove(list.get(list.size()-1));
            return top;
        }
        public static int peek(){
            if(isEmpty()){
                return -1;
            }
            return list.get(list.size()-1);
        }
    }
    public static void main(String args[]){
        Stack s=new Stack();
        s.push(1);
        s.push(2);
        s.push(3);
        s.push(4);
        while(!s.isEmpty()){
            System.out.println(s.peek());
            s.pop();
        }
    }
}