5강 과제 답

lec5_hw.cs

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

namespace lec5_hw
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = 100;
            bool[] sieve = new bool[n];

            sieve[0] = false;
            for (int i = 1; i < n; i++)
            {
                sieve[i] = true;
            }

            for (int i = 2; i < (int)Math.Sqrt(n); i++)
            {
                if (sieve[i-1])
                {
                    for (int j = 2*i; j <= n; j += i)
                    {
                        sieve[j-1] = false;
                    }
                }
            }

            for (int i = 1; i <= n; i++)
            {
                if (sieve[i-1])
                {
                    Console.Write(i);
                    Console.Write(" ");
                }
            }
            Console.ReadKey();
        }
    }
}