Prime

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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {

            int n = 100;
            bool[] prime = new bool[n];
            for (int i = 2; i < n; i++)
                prime[i] = true;

            {
                int i = 2;
                for (; i*i < n; i++)
                    if (prime[i])
                    {
                        Console.WriteLine(i);
                        for (int j = i * i; j < n; j = j + i)
                            prime[j] = false;
                    }
                for (; i < n; i++)
                    if (prime[i])
                    {
                        Console.WriteLine(i);
                    }
            }

            Console.ReadLine();
        }
    }
}