Find sum of 'N' natural numbers.

#include<conio.h>
#include<iostream.h>
void main()
{
  clrscr(); 

  int sum=0,i,num;
  cout<<"Enter a number";
  cin>>num;
  for(i=1;i<=num;i++)
  {
      sum=sum+i;
  }
  cout<<"Sum of "<<num<<"natural numbers = " <<sum; 

  getch();
}