How do I test for integers in MATLAB?

Question

I\'m writing a program that will calculate factorials of integers. However, the part I\'m stuck on is if someone enters a non-integer such as 1.3, I\'d like to

Answer 1

By double command, you cannot get the correct answer:

>> double(uint64(21/22))
ans =
     1
>> double(uint64(22/22))
ans =
     1

also floor,round,... have problem with such cases:

floor(22/22)==21.99999999999999999999999999999999999/22

but mod seems can distinguish 22/22 and 21.99999999999999999999999999999999999/22:

>> mod(22,22)
ans =
     0
>> (21.99999999999999999999999999999999999/22)
ans =
     1