Stack.java

import Exceptions.OverflowException;
import Exceptions.UnderflowException;

import java.util.Scanner;

public class Stack {
 private int[] stack;
 private int size, top;

 Stack() {
 stack = null;
 size = 0;
 top = -1;
 }

 Stack(int size) {
 this.size = size;
 top = -1;
 stack = new int[size];
 }

 public static void main(String[] args) {
 int ch, x;
 Scanner sc = new Scanner(System.in);
 System.out.print("Enter the size of the stack : ");
 int n = sc.nextInt();
 Stack s = new Stack(n);

 loop:
 for (; ; ) {
 System.out.print("1. Push\n" +
 "2. Pop\n" +
 "3. Display\n" +
 "0. Exit\n" +
 "Enter your choice : ");
 ch = sc.nextInt();
 switch (ch) {
 case 0:
 break loop;
 case 1:
 System.out.print("Enter the number you want to push : ");
 x = sc.nextInt();
 try {
 s.push(x);
 } catch (OverflowException e) {
 System.out.println(e.getMessage());
 }
 break;
 case 2:
 try {
 x = s.pop();
 System.out.println(x + " has been popped");
 } catch (UnderflowException e) {
 System.out.println(e.getMessage());
 }
 break;
 case 3:
 s.display();
 break;
 default:
 System.out.println("Dude, seriously?\nI'm sure you can do better than that.\nTry again.");
 }
 System.out.println();
 }
 }

 private boolean isFull() {
 return top >= size - 1;
 }

 private boolean isEmpty() {
 return top == -1;
 }

 private void push(int x) throws OverflowException {
 if (!isFull())
 stack[++top] = x;
 else
 throw new OverflowException("Stack is full");
 }

 private int pop() throws UnderflowException {
 if (!isEmpty())
 return stack[top--];
 else
 throw new UnderflowException("Stack is empty");
 }

 private void display() {
 if (isEmpty()) {
 System.out.println("[]");
 return;
 }
 int i;
 System.out.print("[");
 for (i = 0; i < top; i++)
 System.out.print(stack[i] + ", ");
 System.out.println(stack[i] + "]");
 }
}