Number of ways to write a program of prime number

Question

Number of ways to write logic of prime number

Answer 1

there are as many ways as prime numbers exist

Answer 2

you can check the result of the given number modulu each number below it untill you reach the number 2 and check if every single result doesnt equal to 0.( in this case the number is prime). however, this logic doesnt work for number 2 which is the only even prime number.