How to check a repeat value inside a for loop?

I'm attempting to build Deal or No Deal and for round one a user has to pick 6 cases, I'm stuck on how to check every value they are entering is not a repeat. In this UserCase is the original case they pick to be theirs, as in the game show. I know I have to add another loop somewhere in the mix but I have been stuck on this for hours with no progress.

if true
  % code
end
Round1=[];
for K=1:6
  Case1=input('Choose a case: ');
  while Case1<1 || Case1>26 || mod(Case1,1)~=0 || Case1==UserCase
      Case1=input('Error: Case already chosen, please choose another: '); 
  end
  Round1=[Round1, Case1];
end

Answer 1

[Geoff Hayes]

Marinna - you could create an array to keep track of which cases have been chosen. For example, you could keep track of the state of each case: 0 (false) for not opened, and 1 (true) for opened. Something like

 caseStates = logical(zeros(26,1));

Then, whenever the user chooses a new case via

 chosenCase=floor(input('Choose a case: '));
 while chosenCase < 1 || chosenCase > 26 || caseStates(chosenCase) == true
     chosenCase=floor(input('Error: invalid case. Choose a new case: '));
 end
 caseStates(chosenCase) == true;

Note that you can then check to see if there are any un-opened cases using all as

 if all(caseStates)
     fprintf('There are no unopened cases!\n');
 end

Answer 2

[Image Analyst]

Try this:

% Define call array for the menu() function.
cases = {'1', '2', '3', '4', '5', '6'}
% Define a vector of what cases were picked.
used = false(1, length(cases))
% Let user pick all of the 6 cases.
for k = 1 : 6
  % Let user pick a case.
  button = menu('Choose a case', cases);
  % for next time, remove this case from consideration.
  if button > 0
              % User clicked a valid button.
    cases(button) = [];
    % Let user quit if they want to.
    message = sprintf('Do you want to continue');
    buttonText = questdlg(message, 'Continue?', 'Yes', 'No', 'Yes');
    drawnow;  % Refresh screen to get rid of dialog box remnants.
    if strcmpi(buttonText, 'No')
      return;
    else
    end
  else
    % User clicked white X on red square in upper right of title bar.
    % They want to quit
    break;
  end
end