JavaScript Exercises: Count all the elements in a given stack

JavaScript Stack: Exercise-7 with Solution

Count Stack Elements

Write a JavaScript program to count all the elements in a given stack.

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;
  }
// Returns the number of elements in the stack
 size() {
    return this.items.length;
  }  
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("Number of elements in the said stack:")
console.log(stack.count());
console.log("Input some elements on the stack:")
stack.push(1);
stack.push(4);
stack.push(3);
stack.push(2);
stack.push(5);
stack.push(6); 
console.log(stack.displayStack(stack));
console.log("Number of elements in the said stack:")
console.log(stack.count());
stack.pop(); 
stack.pop();
console.log("Remove two elements from the said stack:")
console.log(stack.displayStack(stack));
console.log("Number of elements in the said stack:")
console.log(stack.count());

Sample Output:

"Initialize a stack:"
"Number of elements in the said stack:"
0
"Input some elements on the stack:"
"Stack elements are:"
"1 4 3 2 5 6"
"Number of elements in the said stack:"
6
"Remove two elements from the said stack:"
"Stack elements are:"
"1 4 3 2"
"Number of elements in the said stack:"
4

Flowchart:

Live Demo:

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

Live Demo:

See the Pen javascript-common-editor by w3resource (@w3resource) on CodePen.

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