Logical operator for strings

I am writing the code for rock, paper, and scissors.

I want to ask users' input, if it's rock, paper, or scissors, I want to store the value to user_choice

if the input is anything else, it will just display an error message.

my code is below, does not matter what I put in for the input, it always go through both if and else section, can anyone explain or help to fix it please?

prompt = 'rock(r),paper(p),or scissors(s)? Make a choice!';
user_choice = input(prompt,'s')
if user_choice == 'r'|user_choice =='p'|user_choice =='s'
    fprintf('Your choice is %s/', user_choice);
else
    display('Please select among r, p, or s');
end

Answer 1

[Image Analyst]

Try it this way:

prompt = 'rock(r),paper(p),or scissors(s)? Make a choice : ';
user_choice = input(prompt, 's');
if ismember(user_choice, {'r', 'p', 's'})
    fprintf('Your choice is %s.\n', user_choice);
else
    warningMessage = sprintf('You entered %s.\nPlease select among r, p, or s ONLY!', user_choice);
	fprintf('%s\n', warningMessage);
    uiwait(warndlg(warningMessage));
end

[Lingbai Ren]

That works! Thanks a lot! Do you mind to explain briefly what the ismember function do?

[Image Analyst]

It basically sees if one item in in a list of other items. See the docuementation for more details.

[Lingbai Ren]

The pop out error windows is cool, thanks!