This task   (the reverse of   URL encoding   and distinct from   URL parser)   is to provide a function
or mechanism to convert an URL-encoded string into its original unencoded form.



Test cases

   The encoded string   "http%3A%2F%2Ffoo%20bar%2F"   should be reverted to the unencoded form   "http://foo bar/".
   The encoded string   "google.com/search?q=%60Abdu%27l-Bah%C3%A1"   should revert to the unencoded form   "google.com/search?q=`Abdu'l-Bahá".


function u = urldecoding(s)
    u = '';
    k = 1;
    while k<=length(s)
        if s(k) == '%' && k+2 <= length(s)
            u = sprintf('%s%c', u, char(hex2dec(s((k+1):(k+2)))));
            k = k + 3;
        else
            u = sprintf('%s%c', u, s(k));
            k = k + 1;
        end        
    end
end