how can i determine why my code is accepting a non integer when it's not suppose to

I'm solving problem that is supposed to only accept an integer as input but its accepting a non integer. I'm attaching the problem and the code i wrote . please help me check what could be wrong thanks

Answer 1

[Roger Stafford]

Your instructions specified that if the input is invalid, you were to return an empty string. This you did not do. Instead your code proceeds just as if the input is valid. When you do an ‘if’ operation terminated by ‘end’, the code proceeds from the point after the ‘end’ unless a ‘break’ or 'continue' has been called. There is no ‘break’ or 'continue' in your code.

Also the test for integer is wrong, in any case. What ‘isinteger’ tests for is whether the input is of TYPE integer which is a different thing from a floating point number being an integer.

In addition you were supposed to test that the input integer does not exceed 3000, otherwise it is invalid.

[OLUBUKOLA ogunsola]

@Roger Stafford i get an error from matlab saying that continue or break statement can only be used for a while and for loop, so i used return and after adjusting my condition check to if margin >1 , cent = [] return . i get the following result Feedback: Your function performed correctly for argument(s) 1 Feedback: Your function performed correctly for argument(s) 99 Feedback: Your function performed correctly for argument(s) 100 Feedback: Your function performed correctly for argument(s) 999 Feedback: Your function performed correctly for argument(s) 1000 Feedback: Your function performed correctly for argument(s) 1001 Feedback: Your function performed correctly for argument(s) 2000 Feedback: Your function performed correctly for argument(s) 2016 Feedback: Your function performed correctly for argument(s) 3000 Feedback: Your function performed correctly for argument(s) 3001 Feedback: Your program made an error for argument(s) [1 2]

[Roger Stafford]

I did not intend that you should use either 'break' or 'continue'. You should have something like this:

   if round(y)~=y | y >= 3000 | y < 0
     cent = ‘’;
   else
     Now do the rest -->

This way you return with an empty string if the input is invalid, and only do the rest of the code if it is valid.

[OLUBUKOLA ogunsola]

this is what it returned : Operands to the and && operators must be convertible to logical scalar values.

[Roger Stafford]

You can only use the "short-circuit" logical operators on scalars, not vectors. Use | and & instead for vectors.

Answer 2

[Image Analyst]

Try something like this:

if y - int32(y) == 0
   % It's an integer.
else
   % It's not an integer
   message = sprintf('%f is not an integer', y);
   uiwait(errordlg(message));
   cent = []; % Return null.
   return;
end

[OLUBUKOLA ogunsola]

@ image analyst , thanks for the suggestion but this is the from incorporating your idea

 Feedback: Your function performed correctly for argument(s) 1
    Feedback: Your function performed correctly for argument(s) 99
    Feedback: Your function performed correctly for argument(s) 100
    Feedback: Your function performed correctly for argument(s) 999
    Feedback: Your function performed correctly for argument(s) 1000
    Feedback: Your function performed correctly for argument(s) 1001
    Feedback: Your function performed correctly for argument(s) 2000
    Feedback: Your function performed correctly for argument(s) 2016
    Feedback: Your function performed correctly for argument(s) 3000
    Feedback: Your function performed correctly for argument(s) 3001
    Feedback: Your program made an error for argument(s) [1 2]

i used if margin >1 and still got same result as above

[Image Analyst]

To handle arrays, try this:

iy = double(int32(y));
if all((y - iy) == 0)
   % It's an integer.
   fprintf('y is an integer\n');
else
   % It's not an integer
   message = sprintf('y is not an integer');
   uiwait(errordlg(message));
   cent = []; % Return null.
   return;
end

[OLUBUKOLA ogunsola]

thanks but same result Feedback: Your function performed correctly for argument(s) 1 Feedback: Your function performed correctly for argument(s) 99 Feedback: Your function performed correctly for argument(s) 100 Feedback: Your function performed correctly for argument(s) 999 Feedback: Your function performed correctly for argument(s) 1000 Feedback: Your function performed correctly for argument(s) 1001 Feedback: Your function performed correctly for argument(s) 2000 Feedback: Your function performed correctly for argument(s) 2016 Feedback: Your function performed correctly for argument(s) 3000 Feedback: Your function performed correctly for argument(s) 3001 Feedback: Your program made an error for argument(s) [1 2]

    Your solution is _not_ correct.

[OLUBUKOLA ogunsola]

i don't know why but when i used this :

 if ~isscalar(y) 
     cent = []; 
elseif y ~= floor(y)
    cent = [];

 it finally worked. but when i tried to combine both conditions on the same line , it didn't 
thanks guys

[Image Analyst]

Your directions were not clear. With 2 numbers, you could have returned 2 numbers, or you could have returned null or some other error condition. Apparently your robo-grader wanted you to just return null if you passed it two numbers because that's what you did and it accepted it.

[OLUBUKOLA ogunsola]

yes, thats what the grader wants