PrimeNumGen

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

namespace primeNumGen
{
    class Program
    {
        static void Main(string[] args)
        {
            List<uint> primeList = new List<uint>();
            Console.WriteLine("The first 1,000,000 prime numbers\nPress Enter to start:");
            Console.ReadLine();
            UInt32 index = 3;
            primeList.Add(2);
            Stopwatch stopWatch = new Stopwatch();
            stopWatch.Start();
            while(primeList.Count < 1000000)
            {
                if (index != 5 && index % 5 == 0)
                {
                    index += 2;
                    continue;
                }
                if (isPrime(index))
                {
                    primeList.Add(index);
                }
                index += 2;
            }
            stopWatch.Stop();
            Console.WriteLine("It took " + (stopWatch.ElapsedMilliseconds * .001).ToString() + " seconds to calculate");
            System.IO.StreamWriter file = new System.IO.StreamWriter("C:\\PrimeNumbers.txt"); //Pick your path
            foreach(uint listItem in primeList)
            {
                file.WriteLine(listItem.ToString());
            }
            file.Close();
            Console.WriteLine("Check downloads folder for file!\nPress Enter to Exit");
            Console.ReadLine();
        }

        public static bool isPrime(uint input)
        {
            if(input < 1)
            {
                return false;
            }
            else
            {
                UInt32 i;
                for (i = 3; i * i <= input; i+=2)
                {
                    if (input % i == 0)
                    {
                        return false;
                    }
                }
            }
            return true;
        }
    }
}