sum of natural numbers using recursion.cpp

#include<iostream>
using namespace std;
long long int sum(long long int n) {//fuction called 'sum' foe calculating the sum of the natural numbers
	if (n == 0)
		return 0;//will return '0' when number will come to 0
	else
		return n + sum(n - 1);//using recursion
}

int main2() {
	cout << "\t\t\t**Program to calculate the sum of natural numbers using recursion**" << endl;
	int num;
	cout << "Please enter the interval: ";
	cin >> num;//inpuing the interval of the numbers
	cout<<"The sum is : "<<sum(num);//calling function 'sum'
	return 0;
}