To check Scalar or Not

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Rakeshwar Elango
Rakeshwar Elango on 29 Jun 2019
Commented: Walter Roberson on 18 Jul 2021
I have debugged the code and now the Scalar test for this code is failing although I have given a provition in the 3rd line of the code to check wheather the given inputs are scalar or not.
please help!
function valid = valid_date(year,month,day)
if nargin==3
if fix(month) && isscalar(month) && fix(day) && isscalar(day) && fix(year) && isscalar(year) && isscalar(valid_date) && year>0 && month>0 && day>0
if mod(year,4)==0&&mod(year,100)~=0 || mod(year,400)==0&&mod(year,100)==0
if ismember(month,[1,3,5,7,8,10,12]) && ismember(day,[1:31])
valid=true;
elseif month==2 && ismember(day,[1:29])
valid=true;
elseif ismember(month,[4,6,9,11]) && ismember(day,[1:30])
valid=true;
else
valid=false;
end
else
if ismember(month,[1,3,5,7,8,10,12]) && ismember(day,[1:31])
valid=true;
elseif ismember(month,[4,6,9,11]) && ismember(day,[1:30])
valid=true;
elseif month==2 && ismember(day,[1:28])
valid=true;
else
valid=false;
end
end
else
valid=false;
end
else
valid=false;
end
Assessment result: correctVarious inputs
Assessment result: incorrectNon-scalar
Return false if an input is not scalar...
Assessment result: correctThe last day of every month
Assessment result: correctRandom leap years
Assessment result: correctRandom non-leap years
Assessment result: correctRandom dates
  6 Comments
Hakan Karapinar
Hakan Karapinar on 17 Jun 2020
if (~isscalar(year) || year < 1 || year ~= fix(year) ) || (~isscalar(month) || month < 1 || month ~= fix(month) ) || (~isscalar(day) || day < 1 || day ~= fix(day) )
valid = false
return ;
check my code out bro.we take same course.:D its worked i passed week 6

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Accepted Answer

Stephen23
Stephen23 on 29 Jun 2019
Edited: Stephen23 on 29 Jun 2019
The reason is likely because of the order you check the inputs with, e.g.:
fix(month) && isscalar(month)
%^^^^^^^^^ what is this supposed to test for?
% ^^^^^^^^^^^^^^ this must be tested first!
If month is non-scalar, then fix(month) will return a non-scalar value, and then this will throw an error because && does not accept non-scalar input values. If you test isscalar first, then for a non-scalar month it will return false (i.e. a scalar!) and then MATLAB does not evaluate anything that follows the &&. Read the documentation to know more:
Note that it is unclear what your fix(...) code is supposed to achieve, but I doubt that it does anything very useful. In any case, the order should be like this:
isscalar(month) && ??? you need to decide what to put here

More Answers (1)

iitm_pnkj
iitm_pnkj on 18 Jul 2021
function valid = valid_date(year, month, day)
m31 = [1 3 5 7 8 10 12];
m30 = [4 6 9 11];
if isscalar(year) == 1 && isscalar(month) == 1 && isscalar(day) == 1 && year > 0 && month > 0 && day > 0
if (mod(year,100) == 0 || mod(year,4) ~= 0) && month == 2 && day <=28
valid = true;
elseif ((mod(year,100) ~= 0 && mod(year,4) == 0) || (mod(year,400) == 0)) && month == 2 && day <= 29
valid = true;
elseif day <= 31 && any(m31(:)== month) == 1
valid = true;
elseif day <= 30 && any(m30(:)== month) == 1
valid = true;
else
valid = false;
end
else
valid = false;
end
end
  1 Comment
Walter Roberson
Walter Roberson on 18 Jul 2021
All those == 1 are unneeded. isscalar() already returns false or true.
The comparisons to 0 are valid, though.

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