In this article, we are going to learn about finding a Factorial of a Number using Recursion. Calculating the factorial of a number using recursion means implementing a function that calls itself to find the factorial of a given number. The factorial of a non-negative integer ānā is the product of all positive integers less than or equal to ānā.
The factorial of a positive number n is given by:
factorial of n (n!) = 1 * 2 * 3 * 4 * . . . * n
Example:
Input : N = 6
Output : The factorial of given number is : 720
Explanation: 6 * 5 * 4 * 3 * 2 * 1 = 720
Hence factorial of 6 is : 720
There are some common approaches that can be used to Find Factorial of Number Using Recursion, which is listed below:
- Factorial using Recursion in JavaScript
- Using Ternary Operator with Recursive Approach
We will explore all the above methods along with their basic implementation with the help of examples.
Approach 1: Factorial using Recursion in JavaScript
To calculate the factorial of a number āNā using recursion, we first establish base cases: if N is 0 or 1, the factorial is 1. Otherwise, we recursively compute N * factorial(N-1) to find the product of all positive integers up to N.
Syntax:
function factorial(n) {
if (n === 0 || n === 1) {
// Code...
}
}
Example: In this example, we are using the above-explained approach.
Javascript
function factorial(n) { Ā Ā Ā Ā if (n === 0 || n === 1) { Ā Ā Ā Ā Ā Ā Ā Ā return 1; Ā Ā Ā Ā } else { Ā Ā Ā Ā Ā Ā Ā Ā return n * factorial(n - 1); Ā Ā Ā Ā } } let num1 = 6; let result = factorial(num1); console.log("The factorial of given number is :" + result); |
The factorial of given number is :720
Approach 2: Using Ternary Operator with Recursive Approach
In this approach the recursive function uses the ternary operator to check if the base case (num === 0) is met, returning 1, otherwise calls itself with (num ā 1) and multiplying num with the result.
Syntax:
condition ? value if true : value if false
Example: In this example, we are using the above-explained approach.
factorial of 10 is, 10! = 10*9*8*7*6*5*4*3*2*1 = 3628800
Javascript
function factorialFunction(num) { Ā Ā Ā Ā return num === 0 ? 1 : num * factorialFunction(num - 1); } Ā Ā const num1 = 10; const result = factorialFunction(num1); console.log(result); |
3628800
