using System;
namespace Example64
{
///
/// Summary description for Class1.
///
class Class1
{
///
/// The main entry point for the application.
///
[STAThread]
static void Main(string[] args)
{
Console.Write("Input n: ");
int n = int.Parse(Console.ReadLine());
Console.WriteLine("The sum of the first {0} integers is: {1} = {2}",
n, sum(n), n * (n +1) / 2);
}
static int sum(int n)
{
if (n == 1)
return 1;
else
return n + sum(n - 1);
}
}
}