Sum of the Series 1 + 2 + 3 + ... + n Using Recursion in C++

In this problem, we are given a number n which defines the nth terms of the series 1^1 + 2^2 + 3^3 + … + n^n. Our task is to create a program that will find the sum of the series.

Let’s take an example to understand the problem,

Input 

n = 4

Output

30

Explanation −sum = (1^1) + (2^2) + (3^3) + (4^4) = 1 + 4 + 9 + 16 = 30.

To solve this problem, we will loop from 1 to n. Find the square of each number. And add each to the sum variable.

Algorithm

Initialize sum = 0
Step 1: Iterate from i = 1 to n. And follow :
   Step 1.1: Update sum, sum += i*i
Step 2: Print sum.

Example

Program to illustrate the working of our solution,

 Live Demo

#include <iostream>
using namespace std;
long long calcSeriesSum(int n) {
   long long sum = 0;
   for( int i = 1; i <= n; i++ )
   sum += (i*i);
   return sum;
}
int main() {
   int n = 7;
   cout<<"Sum of the series 1^1 + 2^2 + 3^3 + ... + "<<n<<"^"<<n<<" is "<<calcSeriesSum(n);
   return 0;
}

Output

Sum of the series 1^1 + 2^2 + 3^3 + ... + 7^7 is 140