C++ program to Find Nth term of the series 1, 1, 2, 6, 24...

In this problem, we are given an integer N. Our task is to create a program to Find Nth term of series 1,1, 2, 6, 24, ...

Let’s take an example to understand the problem,

Input

N = 7

Output

720

Explanation

The series is − 1, 1, 2, 6, 24, 120, 720

Solution Approach

A simple approach to solve the problem is by using the general formula for the nth term of the series. The formula for,

Nth term = (N−1)!

Program to illustrate the working of our solution,

Example

#include <iostream>
using namespace std;
int calcNthTerm(int N) {
   if (N <= 1)
      return 1;
      int factorial = 1;
   for (int i = 1; i < N; i++)
      factorial *= i;
      return factorial;
}
int main() {
   int N = 8;
   cout<<N<<"th term of the series is "<<calcNthTerm(N);
   return 0;
}

Output

8th term of the series is 5040