PrimeTest

using System;

    class PrimeTest
    {
        //Write an expression that checks if given positive integer number
        //n (n ≤ 100) is prime. E.g. 37 is prime.

        static void Main()
        {
            Console.WriteLine("Enter a whole number to test for primality:");
            int userValue = int.Parse(Console.ReadLine());

            if (userValue == 2 || userValue == 3 || userValue == 5 || userValue == 7)
            {
                Console.WriteLine("This is a prime number!");
            }
            else if ((userValue % 2 != 0) && (userValue % 3 != 0) && (userValue % 5 != 0) && (userValue % 7 != 0))
            {
                Console.WriteLine("This is a prime number!");
            }
            else
            {
                Console.WriteLine("This is not a prime number.");
            }
        }
    }