C# Check If Number Is Triangle Number

C# program to check if number is Triangle Number.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

// ? 2017 TheFlyingKeyboard and released under MIT License
// theflyingkeyboard.net

namespace CheckIfNumberIsSquare
{
    class Program
    {
        static void Main(string[] args)
        {
            int num;

            Console.Write("Enter a number: ");
            num = Convert.ToInt32(Console.ReadLine());

            if (isSquare(8 * num + 1))
            {
                Console.Write("Number is triangle number");
            }
            else
            {
                Console.Write("Number is not triangle number");
            }

            Console.ReadKey();
        }

        static bool isSquare(int n)
        {
            for (int i = 0; i < n / 2 + 2; i++)
            {
                if (i * i == n)
                {
                    return true;
                }
            }

            return false;
        }
    }
}