JavaScript Exercises: Top and bottom elements of a stack

JavaScript Stack: Exercise-10 with Solution

Top & Bottom of Stack

Write a JavaScript program to find the top and bottom elements of 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;
  }
  get_Top() {
    return this.items[this.items.length - 1];
  }
  get_Bottom() {
    return this.items[0];
  }
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(6);
stack.push(3);
stack.push(2);
stack.push(5);
stack.push(7); 
console.log(stack.displayStack(stack));
console.log("Top element of the stack is:", stack.get_Top());
console.log("Bottom element of the stack is:", stack.get_Bottom());

Sample Output:

"Initialize a stack:"
"Input some elements on the stack:"
"Stack elements are:"
"1 6 3 2 5 7"
"Top element of the stack is:"
7
"Bottom element of the stack is:"
1 

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.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that retrieves both the top and bottom elements of a stack without modifying it.
• Write a JavaScript function that implements peek operations for both the first and last elements in an array-based stack.
• Write a JavaScript function that returns an object with properties for the top and bottom elements of a stack.
• Write a JavaScript function that validates the stack before attempting to access its top and bottom elements and handles underflow gracefully.

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