Where should I add error checking to my program?

I'm trying to create a program that simulates a dice roll. The instructions given are: Write a matlab funtion called hitTarget that will accept one scalar argument, the target sum of two random 6-sided dice rolls. The function generates and displays two random numbers between 1 and 6 (like dice rolls) until the sum of the two die equals the target argument. Keep track of how many rolls it takes.

Sample Run:

>> hitTarget(8)

          5     2 
          6     3 
          2     2 
          4     3 
          3     5 
   Target met, it took 5 rolls.

My code so far:

function [] = hitTarget( target )

%if(target>=2 && target<=12 && isinteger(target))

    count = 0;
    dieTotal = 0;
    while(dieTotal~=target)
        count = count + 1;
        dieOne = randi(6,1,1);
        dieTwo = randi(6,1,1);
        result = [dieOne dieTwo];
        disp(result);
        dieTotal = sum(result);
        if(dieTotal==target)
            disp(['Target met, it took ', num2str(count), ' rolls.']);
        end
    end
%end
end

I commented out the error checking statement I need because the program will not run at all if I leave it there. But I don't know where else to put it.

Thanks for any help!!!

Answer 1

[Image Analyst]

Replace the line

%if(target>=2 && target<=12 && isinteger(target))

with

if target<2 || target > 12
    errorMessage = sprintf('A target of %d is not allowed.\n', target);
    uiwait(errordlg(errorMessage));
    return;
end
if ~isinteger(target)
    errorMessage = sprintf('Fractional numbers are not allowed!');
    uiwait(errordlg(errorMessage));
    return;
end
% If it gets here, the target number is acceptable.

[Jennifer Coss]

Thanks!