MATLAB Programming - A Guide to MATLAB for Beginners and Experienced Users - page 115

commandpromptorwithinanM-file,withthecommand warning off .There
are several other options for how MATLAB should handle warning messages;
type help warning for details.
In Chapter 4 we used disp to display the output of a command without
printing the “ ans = ” line. You can also use disp to display informational
messages on the screen while an M-file is running, or to combine numerical
output with a message on the same line. For example, the commands
x=2+2;disp(['The answer is ' num2str(x) '.'])
will set x equal to 4 and then print The answer is 4.
MATLAB also has several commands to solicit input from the user run-
ning an M-file. At the end of Chapter 3 we discussed three of them: pause ,
keyboard , and input . Briefly, pause simply pauses execution of an M-file
until the user hits a key, while keyboard bothpauses and gives the user a
prompt to use like the regular command line. Typing return continues ex-
ecuting the M-file. Lastly, input displays a message and allows the user to
enter input for the program on a single line. For example, in a program that
makes successive approximations to an answer until some accuracy goal is
met, you could add the following lines to be executed after a large number of
steps have been taken:
answer = input(['Algorithm is converging slowly; ', ...
'continue (yes/no)? '], 's');
if ~isequal(answer, 'yes')
return
end
Here the second argument 's' to input directs MATLAB not to evaluate
the answer typed by the user, just to assign it as a character string to the
variable answer .Weuse isequal to compare the answer to the string 'yes'
because == can only be used to compare arrays (in this case strings) of the
same length. In this case we decided that if the user types anything but the
full word yes , the M-file should terminate. Other approaches would be to
only compare the first letter answer(1) to 'y' , to stop only if the answer is
'no' , etc.
If a figure window is open, you can use ginput to get the coordinates of a
point that the user selects with the mouse. As an example, the following M-file
prints an “X” where the user clicks:
function xmarksthespot
if isempty(get(0, 'CurrentFigure'))