//Program to calculate the sum of n natural numbers using do while loop formula if you want sum = number * (1 + number)/2

#include<iostream>

using namespace std;

main()

{

 int number, sum = 0, i= 1;

 

 cout << "Enter the nth Number of Natural Number" << endl;

 cin >> number;

 

 do

 {    

     

  sum = sum + i; 

  i++; 

 }

 while(i <= number);

 

 cout << "the sum upto "<< number << "th Natural Number is : " << sum;

 

 return 0;

}