How do I use a while loop to keep asking for input of even numbers?

How do I aks user to input an even number but if the number is odd or equal to 0, it should keep asking for input?

Answer 1

[KSSV]

prompt = 'Enter a number:';

S = input(prompt) ;

if mod(S,2)
    S = input(prompt) ;
end

[adena0]

thanks but, this was my code originally and it failed after enteriing and odd number twice. i think a while loop needs to be used i just don't know how