Stack Implementation using Array in Java

Stack Implementation using Array

Last Updated: 19 January, 2025 🕓 5 Mins

In this tutorial page, we are going to learn about how to implement a stack data structure using an array in Java.

By the end of this tutorial, you will have a clear understanding of both stack operations and how to effectively utilize an Array in Java. This knowledge will help you to manage data more efficiently.

Stack data structure implementation

There are two ways to implement a stack data structure:

Using Array

Using Linked List

Let's see the Stack implementation using Array in Java.

Stack implementation using Array in Java

In an array-based stack implementation, the push operation is implemented by incrementing the index of the top element and storing the new element at that index. The pop operation is implemented by decrementing the index of the top element and returning the value stored at that index.

  class Stack {
    private int array_size = 100;     // size of the array
    private int top;                  // top of the stack
    private int[] array;              // stack array
  
    // constructor
    Stack() {
      array = new int[array_size];
      top = -1;
    }
  
    // Method to check stack is empty or not
    // Returns true if stack is empty else false
    boolean isEmpty() {
      if (top < 0) {
        System.out.println("Stack is empty, cannot pop element.");
        return true;
      }
      return false;
    }
  
    // Method to check stack is full or not
    // Returns true if stack is full else false
    public boolean isFull() {
      if (top == array_size - 1) {
        System.out.println("Stack is full, cannot push new item.");
        return true;
      }
      return false;
    }
  
    // Adding new item into the stack
    void push(int item) {
      if (!isFull()) {
        // increment top by 1 and insert item into the array
        array[++top] = item;
        System.out.println(item + " pushed into the stack.");
      }
    }
  
    // Removing an item from the stack
    void pop() {
      if (!isEmpty()) {
        int item = array[top--];
        System.out.println(item + " popped from the stack.");
      }
    }
  
    // Returns the top element of the stack.
    void peek() {
      if (!isEmpty()) {
        int item = array[top];
        System.out.println("Stack top item: " + item);
      }
    }
  
    // Print stack all elements
    void printStack() {
      System.out.print("Stack Items:");
      for (int i = top; i > -1; i--) {
        System.out.print(" " + array[i]);
      }
    }
  }
  
  // Driver code
  public class StackUsingArray {
    public static void main(String args[]) {
      Stack stack = new Stack();
      stack.push(10);
      stack.push(20);
      stack.push(30);
      stack.push(40);
      stack.pop();
      stack.peek();
      stack.printStack();
    }
  }

10 pushed into the stack.
20 pushed into the stack.
30 pushed into the stack.
40 pushed into the stack.
40 popped from the stack.
Stack top item: 30
Stack Items: 30 20 10