# JavaScript Exercises: Sort the elements of a stack in descending order

## JavaScript Stack: Exercise-2 with Solution

Write a JavaScript program to sort the elements of a given stack in descending order.

Sample Solution:

JavaScript Code:

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

// Pushes an element onto the stack
push(element) {
this.items.push(element);
}

// Removes the top element from the stack and returns it
pop() {
if (this.items.length == 0)
return "Underflow";
return this.items.pop();
}

// Checks if the stack is empty
isEmpty() {
return this.items.length == 0;
}

// Returns the top element of the stack
peek() {
if (this.items.length == 0)
return "No elements in Stack";
return this.items[this.items.length - 1];
}

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();
}

sort_Stack(stack) {
// Create a temporary stack to hold sorted elements
let tempStack = new Stack();

while (!stack.isEmpty()) {
// Pop the top element from the original stack
let currentElement = stack.pop();

// Move all elements greater than currentElement from tempStack back to stack
while (!tempStack.isEmpty() && tempStack.peek() > currentElement) {
stack.push(tempStack.pop());
}

// Push the currentElement onto the tempStack
tempStack.push(currentElement);
}

// Move all elements from tempStack back to stack
while (!tempStack.isEmpty()) {
stack.push(tempStack.pop());
}
return stack;
}
}
console.log("Initialize a stack:")
let stack = new Stack();
console.log("Input some elements on the stack:")
stack.push(1);
stack.push(4);
stack.push(3);
stack.push(2);
stack.push(5);
console.log(stack.displayStack(stack));
stack.sort_Stack(stack);
console.log("Sort the elements of the stack in descending order:")
console.log(stack.displayStack(stack));
console.log("Remove one element and insert two elements:")
stack.pop();
stack.push(0);
stack.push(8);
console.log(stack.displayStack(stack));
stack.sort_Stack(stack);
console.log("Sort the elements of the stack in descending order:")
console.log(stack.displayStack(stack));
```
```

Sample Output:

```Initialize a stack:
Input some elements on the stack:
Stack elements are:
1 4 3 2 5
Sort the elements of the stack in descending order:
Stack elements are:
5 4 3 2 1
Remove one element and insert two elements:
Stack elements are:
5 4 3 2 0 8
Sort the elements of the stack in descending order:
Stack elements are:
8 5 4 3 2 0
```

Flowchart:

Live Demo:

See the Pen javascript-stack-exercise-2 by w3resource (@w3resource) on CodePen.

Improve this sample solution and post your code through Disqus

Stack Previous: Implement a stack with push and pop operations.
Stack Exercises Next: Sort the elements of a stack in ascending order.

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﻿

## JavaScript: Tips of the Day

Creates an array of elements, ungrouping the elements in an array produced by zip and applying the provided function

Example:

```const tips_unzip = (arr, fn) =>
arr
.reduce(
(acc, val) => (val.forEach((v, i) => acc[i].push(v)), acc),
Array.from({
length: Math.max(...arr.map(x => x.length))
}).map(x => [])
)
.map(val => fn(...val));

console.log(tips_unzip([[2, 15, 200], [3, 25, 300]], (...args) => args.reduce((acc, v) => acc + v, 0)));
```

Output:

```[5, 40, 500]
```