StackUsingArray.java

import java.util.*;
public class StackUsingArray {
    public static class Stack{
        static int arr[]=new int[5];
        static int i=-1;
        public static boolean isFull(){
            return i==arr.length-1;
        }
        public static boolean isEmpty(){
            return i==-1;
        }
        public static void push(int data){
            if (Stack.isFull()){
                System.out.println("Stack iverflow");
                return;
            }
            i++;
            arr[i]=data;
        }
        public static int pop(){
            if (i==-1){
                return -1;
            }
            int top=arr[i];
            i--;
            return top;
        }
        public static int peek(){
            if (i==-1){
                return -1;
            }
            return arr[i];
        }
    }
    public static void main(String[] args) {
        Stack.push(30);
        Stack.push(20);
        Stack.push(10);
        while(!Stack.isEmpty()){
            System.out.println("Top: " + Stack.peek());
            Stack.pop();
        }
    }
}