CustomStack.java

package com.sarvesh.javabasics;

public class CustomStack {
 private int[] arr;
 private int top;
 private int capacity;

 public CustomStack(int size) {
 this.arr = new int[size];
 this.capacity = size;
 this.top = -1; 
 }

 public void push(int x) {
 if (top == capacity - 1) {
 System.out.println("System Crash: Stack Overflow");
 return;
 }
 arr[++top] = x;
 }

 public int pop() {
 if (top == -1) {
 System.out.println("System Crash: Stack Underflow");
 return -1;
 }
 return arr[top--];
 }

 public int peek() {
 if (top == -1) return -1;
 return arr[top];
 }

 public static void main(String[] args) {
 CustomStack engine = new CustomStack(5);
 engine.push(10);
 engine.push(20);
 
 System.out.println("Popped: " + engine.pop());
 System.out.println("Peek: " + engine.peek()); 
 }
}