How to check a given number is prime or not in c# asp.net?

Defintion 

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. 

Here is a c# source code to check a given number is prime or not:-

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleDemoApp
{
    class test
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Enter a number to check its a prime :-");
            int num = Convert.ToInt32(Console.ReadLine());
            int result = CheckFor_Prime(num);
            if (result == 0)
            {
                Console.WriteLine("{0} is not a prime number!", num);
            }
            else
            {
                Console.WriteLine("{0} is  a prime number", num);
            }
            Console.Read();
        }
        private static int CheckFor_Prime(int number)
        {
            int i;
            for (i = 2; i <= number - 1; i++)
            {
                if (number % i == 0)
                {
                    return 0;
                }
            }
            if (i == number)
            {
                return 1;
            }
            return 0;
        }
    }
}

Ouput:-

Enter a number to check its a prime :- 67
67 is not a prime number!


Enter a number to check its a prime :-77
77 is a prime number

Enter a number to check its a prime :- 29
29 is not a prime number!


Here is a source code example to print prime number between 1 and 100 :-

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleDemoApp
{
    class test
    {
        static void Main(string[] args)
        {
            bool isPrimeNum = true;
            Console.WriteLine("Prime Numbers between 1 and 100 are:- ");
            for (int i = 2; i <= 100; i++)
            {
                for (int j = 2; j <= 100; j++)
                {

                    if (i != j && i % j == 0)
                    {
                        isPrimeNum = false;
                        break;
                    }

                }
                if (isPrimeNum)
                {
                    Console.Write("\t" + i);
                }
                isPrimeNum = true;
            }
            Console.ReadKey();
        }
    }
}

Outtput:-

Prime Numbers : 
      2 3 5 7 11 13 17 19 23 29
31 37 41 43 47 53 59 61 67 71
73 79 83 89 97