Hackerrank Day 9: Recursion 3 | Hackerrank Solutions in C++

Objective
Today, we're learning and practicing an algorithmic concept called Recursion. Check out the Tutorial tab for learning materials and an instructional video!

Recursive Method for Calculating Factorial

Task
Write a factorial function that takes a positive integer,  as a parameter and prints the result of  ( factorial).

Note: If you fail to use recursion or fail to name your recursive function factorial or Factorial, you will get a score of .

Input Format

A single integer,  (the argument to pass to factorial).

Constraints

• Your submission must contain a recursive function named factorial.

Output Format

Print a single integer denoting .

Sample Input

3

Sample Output

6

Explanation

Consider the following steps:

From steps  and , we can say ; then when we apply the value from  to step , we get . Thus, we print  as our answer.

Here is the Solution

#include <iostream>

using namespace std;

int factorial(int n) {

    if (n == 1) return 1;

    return factorial(n - 1) * n;

}

int main() {

    int N;

    cin >> N;

    cout << factorial(N);

    return 0;

}