function not working properly

i have this function, which is supposed to get three numbers and check if they're scalars and bigger than one

function valid = valid_date (year,month,day)
if ~isscalar(year)||year<1
    valid=~1;
elseif  ~isscalar(month)||month<1||month>12
    valid=~1;
elseif ~isscalar(day)||day<1
    valid=~1;
end

but when i give it

valid_date(2019,4,0)

or

valid_date(1,1,0)

it should give a logical 0 but it gives a 1

ans =

  logical

   1

it works correctly with (0,1,1) or (0,1,0) or (1,0,1) but this specific combination seems to break it

how do i fix it?

Answer 1

[Walter Roberson]

The code you post only assigns to valid in situations where it has valid=~1 so it can only ever assign false (0) to valid. There is no case in which the code can return 1 for valid.