recursive function to check a Palindrome

function out=palindrome(x)

n=numel(x);

if n==1

out=true;

else

Can anyone continue from here?

Answer 1

[John D'Errico]

Why not try? I won't write it for you, as the entire problem is to make you think. I'll give you one hint, and I will hope nobody does the rest of your homework for you.

A vector is a palindrome if the first and last elements are the same, AND...

.... what else? That is, what information do you need about the rest of the vector? Is there some way you can treat this in a recursive way?

This is your homework, not ours, remember.

[Harsh Mittal]

I tried writing the code but i am getting error as "MATLAB:TooManyOutputs" , can anyone help me resolve this error, i recieved this error while submiting my code

Answer 2

[xin yi leow]

function t=palindrome(char)
    if length(char)==2
        if char(1)==char(2)
            t=true 
        else 
            t=false
        end
    elseif length(char)==1
        t=true
    else 
        if char(1)==char(end)
           char(1)=[];
           char(end)=[]
           t=palindrome(char)
        else 
           t=false
        end
    end
end

Answer 3

[Johannes Hougaard]

There is no need to make it recursive or to look for multiple numel's

function out = palindrom(x)
    x = upper(char(varargin{1})); % to account for inputs being UPPER/lower case and/or a string rather than a char
    n = length(x);
    iseven = rem(n,2) == 0;
    middle = ceil(n/2);
    if ~iseven        
        out = all(x(1:middle) == fliplr(x(middle:end)));
    else       
        out = all(x(1:middle) == fliplr(x(middle+1:end)));
    end
end

[Image Analyst]

It's probably a requirement for his homework.

But your function could be done simply like this:

palindrome = isequal(lower(s), fliplr(lower(s)))

No need to worry about length and which character is in the middle.

[Johannes Hougaard]

Valid point - classic example of overthinking a simple problem :S

[Urmish Haribhakti]

Correct. Obviously, very simple to do it normally. Any idea on how to make it recursive?

[Selvakumar T]

function Result = palindrome(t) if length(t) <= 1 Result= true; else Result= (t(1) == t(end) &&palindrome(txt(2:end-1))); end end

Answer 4

[Wai Han]

Hello Urmish Haribhakti,

I suggest you to try your best like John D'Errico said.

But somehow, I can help you out by telling you the concept, (maybe a pseudocode).

% The input is a string which is in term a char array.
% Firstly, if the length of the string is 1, or isempty!! then the function should return logical 1 (true).
% elseif length ~= 1,check the first and last value of the vector,
%   if first == last
% recall the function by removing those two values. for example, vector(2:end-1)
% Lastly, if the first and last value are not equal, the your output should be logical 0 (false).

I hope this can help you out!