Task

Write a function/procedure/subroutine that is called with an integer value and returns the middle three digits of the integer if possible or a clear indication of an error if this is not possible.

Note: The order of the middle digits should be preserved.

Your function should be tested with the following values; the first line should return valid answers, those of the second line should return clear indications of an error:

123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345
1, 2, -1, -10, 2002, -2002, 0

Show your output on this page.




function s=middle_three_digits(a)
% http://rosettacode.org/wiki/Middle_three_digits
 
s=num2str(abs(a));
 
if ~mod(length(s),2)
	s='*** error: number of digits must be odd ***';
	return;
end; 
if length(s)<3,
	s='*** error: number of digits must not be smaller than 3 ***';
	return;
end;
 
s = s((length(s)+1)/2+[-1:1]);