Program to find sum of first n natural numbers

#include<iostream.h>
#include<conio.h>
void main()
{      
clrscr();
int i,n,sum=0;
cout<<"\n Enter Number at which you want to sum : ";
cin>>n;
for(i=1;i<=n;++i)
{
sum+=i;
}
cout<<"\n\t SUM is : "<<sum;
getch();
}


                                                    Output