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recursive function to check a Palindrome

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Urmish Haribhakti
Urmish Haribhakti on 10 Sep 2020
Answered: xin yi leow on 25 Jan 2021
function out=palindrome(x)
n=numel(x);
if n==1
out=true;
else
Can anyone continue from here?

Answers (4)

John D'Errico
John D'Errico on 11 Sep 2020
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.
  1 Comment
Harsh Mittal
Harsh Mittal on 20 Oct 2020
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

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xin yi leow
xin yi leow on 25 Jan 2021
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

Johannes Hougaard
Johannes Hougaard on 10 Sep 2020
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
  4 Comments
Selvakumar T
Selvakumar T on 25 Sep 2020
function Result = palindrome(t) if length(t) <= 1 Result= true; else Result= (t(1) == t(end) &&palindrome(txt(2:end-1))); end end

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Wai Han
Wai Han on 18 Oct 2020
Edited: Wai Han on 18 Oct 2020
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!

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