function guess_letter
%
% Play a guessing game with the user.  Pick a letter, then ask her
% to guess it.  Quit when she succeeds.
%

% this is the letter -- the user has to guess it
letter = 'p';
finished = 0;
while (finished == 0)
	
	% prompt the user, and put her result in the variable "guess"
	guess = input('I am thinking of a letter.  Which is it? ', 's');
	
	% now use "strcmp" to compare the guess and the actual letter
	if (strcmp(guess, letter) == 1)
		fprintf(1, 'yes, that is correct -- it was %s\n', letter);
		finished = 1;
	else
		fprintf(1, 'nope, that is not right\n');
	end
end