What is wrong with my function? (Lesson 5 wrap up assignment)

function valid = valid_date (year,month,day)

if nargin <3
    valid = false;
    return
end

if (isscalar(year)) && (year >= 1) && (year == fix(year))
    valid = true;
elseif (isscalar(month)) && (month >= 1) && (month==fix(month))
    valid = true;   
elseif (isscalar(day)) && (day >= 1) && (day == fix(day))
    valid = true;
else
    valid = false;
end

if ((rem(year,4) == 0) || (rem(year,400)==0)) && (rem(year,100)~=0)  
    if (month == 2) && (day<30)
        valid = true;
    elseif (month == 1||3||5||7||9||11) && (day<32) 
        valid = true;
    elseif (month == 4||6||8||10||12) && (day<31)
        valid = true;
    else
        valid = false;
    end
else
    valid = false;
    return
end
       
if (month == 1||3||5||7||9||11) && (day<32)
    valid = true;
elseif (month ==2) && (day<29)
    valid = true;
elseif (month == 4||6||8||10||12) && (day<31)
    valid = true;
else
    valid = false;
end
end

Answer 1

[IMAD ACHAHBOUN]

function [valid] = valid_date(year,month,day)
if nargin==3
    if month==fix(month) && isscalar(month) && day==fix(day) && isscalar(day) && year==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

Answer 2

[Abhishek Inamdar]

function valid = valid_date (year, month, day)
if nargin == 3
    if isscalar(month) && isscalar(day) && isscalar(year) && month==fix(month) && day==fix(day) && year==fix(year) && 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

Keep isscalar first in the line 3 is importatnt, first we need to check scalar