In C#:

Design and implement a program that asks the user to enter a non-zero positive number and determines if a number entered by the user is a prime number. A prime number is a number that is divisible only by 1 and itself. 2, 3, 5 and 7 are prime numbers. 4 and 9 are not prime numbers. The program should validate the input in a reasonable way. The program should ask the user if he/she/they want to check another number after the result has been displayed and should repeat the process as long as the user enters yes.