How to make an if condition where strings are involved?

Hi, so this is my code,

alphabet = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
letter = input('Enter a letter: ','s');
count = 0;
while any(strcmp(alphabet,letter));
    count = count + 1;
    fprintf('Thanks, you enter a %s\n',letter);
    letter = input('Enter a letter: ','s');
    if letter~=alphabet
        fprintf('%d is not a letter\n',letter)
    end
end
fprintf('You entered %d letters\n',count);

I need to show that when a nonletter is entered, for example 3, the output will be 3 is not a letter.

I get this error regarding the if condition,

Enter a letter: d

Thanks, you enter a d

Enter a letter: f

Undefined operator '~=' for input arguments of type 'cell'.

Error in printloveletters (line 16)

if letter~=alphabet

What should I put as the if condition to make it work?

Thanks!

Answer 1

[madhan ravi]

 if ~ismember(letter, alphabet)
    fprintf('%s is not a letter\n', letter)
 end

[Roxanne Esguerra]

This works! Thank you so much!

Answer 2

[Alan Stevens]

Try replacing

letter~=alphabet

with

~any(strcmp(alphabet,letter))

[Roxanne Esguerra]

Thanks, I appreciate the help!

Answer 3

[Sumeet Singh]

    if ~ismember(letter,alphabet)
        fprintf('%d is not a letter\n',letter)
    end

You can't use operator '~=' for operands of type cell (alphabet, a cell array in your case).

[Roxanne Esguerra]

Thanks, I appreciate the help!