C# Program to Check Whether the Given Number is a Prime number or not.

This C# Program Checks Whether the Given Number is a Prime number or not.
It will ask a user to enter a number and check whether it is prime or not.

using System;

namespace CsharpProgram
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter a Number : ");

            int _Number;

            _Number = Convert.ToInt32(Console.ReadLine());

            int _Flag;

            _Flag = 0;

            for (int i = 1; i <= _Number; i++)
            {
                if (_Number % i == 0)
                {
                    _Flag++;
                }
            }

            if (_Flag == 2)
            {
                Console.WriteLine("Entered Number is a Prime Number.");
            }
            else
            {
                Console.WriteLine("Not a Prime Number");
            }
            Console.ReadKey();
        }
    }
}