Program to calculate the sum of numbers from 1 to n using recursion in C++.

Solution

#include <iostream>

using namespace std;

int sum(int n) {
  if (n != 0)
    return n + sum(n - 1);
  else
    return n;
}

int main()
{
    int n,ans;
    cout<<"Enter a Number ";
    cin>>n;
    ans=sum(n);
    cout<<"Sum of first n natural number is :- "<<ans;
    return 0;
}

Output :

Enter a Number
10
Sum of first n natural number is :- 55