JavaScript Exercises: Rotate the stack elements to the left

JavaScript Stack: Exercise-11 with Solution

Rotate Stack Left

Write a JavaScript program to rotate the stack elements to the left direction.

Sample Solution:

JavaScript Code:

class Stack {
  constructor() {
    this.items = [];
  }

  push(element) {
    this.items.push(element);
  }

  pop() {
    if (this.isEmpty())
      return "Underflow";
    return this.items.pop();
  }

  peek() {
    if (this.isEmpty())
      return "No elements in Stack";
    return this.items[this.items.length - 1];
  }

  isEmpty() {
    return this.items.length === 0;
  }

 rotateLeft() {
    if (this.isEmpty()) {
      return "Underflow";
    }
    let firstElement = this.items.shift();
    this.items.push(firstElement);
    return this.items;
  }
displayStack(stack) {
  console.log("Stack elements are:");
  let str = "";
  for (let i = 0; i < stack.items.length; i++)
    str += stack.items[i] + " ";
  return str.trim();
 }        
}
console.log("Initialize a stack:")
let stack = new Stack();
console.log("Input some elements on the stack:")
stack.push(1);
stack.push(2);
stack.push(3);
stack.push(4);
stack.push(5);
console.log(stack.displayStack(stack));
console.log("Rotate the stack elements to the left:")
console.log(stack.rotateLeft());
console.log("Again rotate the stack elements to the left:")
console.log(stack.rotateLeft());
console.log("Again rotate the stack elements to the left:")
console.log(stack.rotateLeft());

Sample Output:

Initialize a stack:
Input some elements on the stack:
Stack elements are:
1 2 3 4 5
Rotate the stack elements to the left:
[2,3,4,5,1]
Again rotate the stack elements to the left:
[3,4,5,1,2]
Again rotate the stack elements to the left:
[4,5,1,2,3]

Flowchart:

Live Demo:

* To run the code mouse over on Result panel and click on 'RERUN' button.*

Live Demo:

See the Pen javascript-stack-exercise-11 by w3resource (@w3resource) on CodePen.

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