First, lets review
if ((i / 2)!= 0)
{
Console.WriteLine(i + "\t is prime");
continue;
}
If
i
is 4 and you divide it by 2, you get 2 which is not 0 and hence you get into the
if
part of the condition.
Second, if you need to know whether your number is a prime number or not, your logic needs to be different.
You cannot divide by just 2 and find out. 9 for e.g. is not divisible by 2 but still not a prime number.
Prime numbers -
https://en.wikipedia.org/wiki/Prime_number[
^].