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Rakeshwar Elango

Rakeshwar Elango (view profile)

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Write a function called valid_date that takes three positive integer scalar inputs year, month, day. If these three represent a valid date, return a logical true, otherwise false. The name of the output argument is valid.

Asked by Rakeshwar Elango

Rakeshwar Elango (view profile)

on 27 Jun 2019
Latest activity Commented on by Rakeshwar Elango

Rakeshwar Elango (view profile)

on 29 Jun 2019
Hi Folks,
I have tried and ended up in errors. For example(valid_date(2018, 4, 1) failed,The last day of every month
Variable valid has an incorrect value. valid_date(2000, 1, 31) failed..., Random leap years
Variable valid has an incorrect value. valid_date(1624, 2, 29) failed..., Random dates
Variable valid has an incorrect value. valid_date(1433, 6, 28) failed...)
Kindly point out the errors I have made!
function valid = valid_date(year,month,day)
if (nargin==3)
if (fix(valid_date)&&isscalar(valid_date))
if((rem(year,4)==0||rem(year,400)==0) && rem(year,100)~=0)
if((month==1||3||5||7||9||11) && 0<day<32)
valid=true;
elseif(month==2 && 0<day<30)
valid=true;
elseif((month==4||6||8||10||12) && 0<day<31)
valid=true;
else
valid=false;
end
else
if((month==1||3||5||7||9||11) && 0<day<32)
valid=true;
elseif((month==4||6||8||10||12) && 0<day<31)
valid=true;
elseif(month==2 && 0<day<29)
valid=true;
else
valid=false;
end
end
else
valid=false;
end
else
valid=false;
end

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Guillaume

Guillaume (view profile)

on 27 Jun 2019
As Stephen points out, inventing your own syntax for the if tests is not going to work very well. Note that to check if a number is a member of the set {a,b,c}, you'd use ismember(x, [a, b, c]), not some invented x==a||b||c syntax.
In this case, it didn't even matter that the comparison didn't make sense because of:
if fix(valid_date)&&isscalar(valid_date) %removed unnecessary parentheses
%...
end
which recurse into valid_date, this time with no argument. Since valid_date with 0 inputs always return false (thankfully, breaking the recursion), and since fix(false) is always false, the above if is always false.
As coded, the function can be simply reduced to
function valid = valid_date(~, ~, ~)
valid = false;
end
Rakeshwar Elango

Rakeshwar Elango (view profile)

on 28 Jun 2019
Thank you Stephen and Guillaume as the newly invented statement of me didn't through any error so I was wandering wheather where it went wrong. Thank you for your suggesion!
Rakeshwar Elango

Rakeshwar Elango (view profile)

on 29 Jun 2019
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

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1 Answer

James Tursa

James Tursa (view profile)

Answer by James Tursa

James Tursa (view profile)

on 27 Jun 2019
 Accepted Answer

Looks like you are taking the same class as Rahul. Rather than repeat my answer here, I will simply direct you to the link:
https://www.mathworks.com/matlabcentral/answers/466971-if-else-problem-for-year

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