Recursive Method
- Declare a variable with a value of the number whose factorial you have to find.
- Declare a recursive function factorial taking the value as a parameter.
- The function returns 1 if the value is 0 else the return calls the function for value – 1.
- After recursion is over the value returned is the factorial.
Example: In this example, we are following Recursive method
let n = 5;
function factorial(n) {
if (n === 0) {
return 1;
}
else {
return n * factorial( n - 1 );
}
}
console.log(factorial(n));
Output
120
Time Complexity: O(n) Since the code is running for all the values of n
Space Complexity: O(n) As the stack is being created for each function call
Factorial of a number using JavaScript
The factorial of a non-negative integer is the product of all positive integers less than or equal to that number. It’s denoted by “n!” where n is the integer. Factorial represents the number of permutations or arrangements of a set.
Note: Factorials of negative numbers are not defined as only positive numbers including 0 are defined in the domain of factorials.
Examples:
Input : 4
Output : 24
Input : 5
Output : 120
Table of Content
- Approach 1: Iterative Method
- Approach 2: Recursive Method
- Approach 3: Memoization Method