We will be writing two JavaScript functions, the job of both the functions will be to take in a number and return its factorial.
The first function should make use of a for loop or while loop to compute the factorial. Whereas the second function should compute the factorial using a recursive approach.
Lastly, we should compare the times taken by these functions over a large number of iterations.
Example
Following is the code −
const factorial = (num = 1) => { let result = 1; for (let i = 2; i <= num; i += 1) { result *= i; } return result; } const factorialRecursive = (num = 1) => { if(num > 1){ return num * factorialRecursive(num - 1); }else{ return 1; } }; const ITERATIONS = 100000000; const num = 12; console.time('Looping Approach'); for(let i = 0; i < ITERATIONS; i++){ factorial(num); }; console.timeEnd('Looping Approach'); console.time('Recursive Approach'); for(let j = 0; j < ITERATIONS; j++){ factorialRecursive(num); }; console.timeEnd('Recursive Approach');
Output
Following is the output on console −
Looping Approach: 886.720ms Recursive Approach: 6526.203ms
This time taken will vary from machine to machine by the ratio is bound to remain more or less the same.