JavaScript Exercises: Implement a stack using a linked list

JavaScript Stack: Exercise-21 with Solution

Linked List Stack Implementation

Write a JavaScript program to implement a stack using a linked list with push and pop operations. Find the top element of the stack and check if the stack is empty or not.

Sample Solution:

JavaScript Code:

class Node {
  constructor(data) {
    this.data = data;
    this.next = null;
  }
}

class Stack {
  constructor() {
    this.top = null;
    this.size = 0;
  }
  push(data) {
    const node = new Node(data);
    node.next = this.top;
    this.top = node;
    this.size++;
  }

  pop() {
    if (this.isEmpty()) {
      return null;
    }
    const data = this.top.data;
    this.top = this.top.next;
    this.size--;
    return data;
  }

  peek() {
    if (this.isEmpty()) {
      return null;
    }
    return this.top.data;
  }

  isEmpty() {
    return this.size === 0;
  }

  getSize() {
    return this.size;
  }

 displayStack(stack) {
  let tempStack = new Stack();

  // Copy all elements from the original stack to a temporary stack
  while (!stack.isEmpty()) {
    tempStack.push(stack.pop());
  }
  let str = "";
  while (!tempStack.isEmpty()) {
    let element = tempStack.pop();
    stack.push(element);
    str += element + " ";
  }
    console.log(str);
 }
   
}

console.log("Initialize a stack using a linked list:")
let stack = new Stack();
console.log("Is the stack empty?");
console.log(stack.isEmpty()); 
console.log("Input some elements on the stack:")
stack.push(1);
stack.push(2);
stack.push(3);
stack.push(4);
stack.push(5);
stack.displayStack(stack);
console.log("Top of the element of the stack:");
console.log(stack.peek()); 
console.log("Size of the stack:");
console.log(stack.getSize()); 
console.log("Remove one element from the stack:")
stack.pop();
stack.displayStack(stack);
console.log("Top of the element of the stack:");
console.log(stack.peek());  
console.log("Is the stack empty?");
console.log(stack.isEmpty());
console.log("Size of the stack:");
console.log(stack.getSize());

Sample Output:

Initialize a stack using a linked list:
Is the stack empty?
true
Input some elements on the stack:
1 2 3 4 5 
Top of the element of the stack:
5
Size of the stack:
5
Remove one element from the stack:
1 2 3 4 
Top of the element of the stack:
4
Is the stack empty?
false
Size of the stack:
4

Flowchart:

Live Demo:

See the Pen javascript-stack-exercise-20 by w3resource (@w3resource) on CodePen.

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