Java program to implement Stack

// Stack implementation in Java

class Stack {

  // store elements of stack

  private int arr[];

  // represent top of stack

  private int top;

  // total capacity of the stack

  private int capacity;

  // Creating a stack

  Stack(int size) {

    // initialize the array

    // initialize the stack variables

    arr = new int[size];

    capacity = size;

    top = -1;

  }

  // push elements to the top of stack

  public void push(int x) {

    if (isFull()) {

      System.out.println("Stack OverFlow");

      // terminates the program

      System.exit(1);

    }

    // insert element on top of stack

    System.out.println("Inserting " + x);

    arr[++top] = x;

  }

  // pop elements from top of stack

  public int pop() {

    // if stack is empty

    // no element to pop

    if (isEmpty()) {

      System.out.println("STACK EMPTY");

      // terminates the program

      System.exit(1);

    }

    // pop element from top of stack

    return arr[top--];

  }

  // return size of the stack

  public int getSize() {

    return top + 1;

  }

  // check if the stack is empty

  public Boolean isEmpty() {

    return top == -1;

  }

  // check if the stack is full

  public Boolean isFull() {

    return top == capacity - 1;

  }

  // display elements of stack

  public void printStack() {

    for (int i = 0; i <= top; i++) {

      System.out.print(arr[i] + ", ");

    }

  }

  public static void main(String[] args) {

    Stack stack = new Stack(5);

    stack.push(1);

    stack.push(2);

    stack.push(3);

    System.out.print("Stack: ");

    stack.printStack();

    // remove element from stack

    stack.pop();

    System.out.println("\nAfter popping out");

    stack.printStack();

  }

}