Error Messages

Hi Folks,

I have generated my code depending on what the user inputs. So, my questions in the command window is basically numbers corresponding to particular Methods that I have coded. However, now, if the user inputs a character or number outside those input number range the question asks, by mistake, the code continues and gives an error later down. I would like it to stop there temperarily and requestion the user with the same question until he/she gets it correct.

disp('Please Enter the Method:')
disp('1 – Aligrot Method')
disp('2 – Pishinger Method')
disp('3 – Watson Method')

    UserInput = input('Enter the Number corresponding to the selective Method and Press ENTER: ');

    if UserInput == 1

      … %calls a set of functions

    elseif UserInput == 2

      … %calls a set of functions

    elseif UserInput == 3

      … %calls a set of functions

    elseif 3 < UserInput < 1 || ischar(UserInput )

            error('PLEASE READ CAREFULLY!!'); 
                                   
    end

Thanks

[Daniel Shub]

What is the problem you are having? What happens and what do you expect to happen?

[Ferd]

Suppose the User enters a number 5(say). The number 5 doesn't correspond to those numbers I've specified. I would like it to requestion the User to input the correct number, hence the correct Method. Similarly, if the user inputs a letter it should do the same, ask the question again until the right number is selected.

Answer 1

[Daniel Shub]

Your if statement can be made to work, but I think a switch statement is a little cleaner.

doc switch

There are lots of ways of handling the exiting from the loop. You might want to use

doc break

I went with a TF flag that is either true or false.

TF = true;
while TF
TF = false;
disp('Please Enter the Method:')
disp('1 – Aligrot Method')
disp('2 – Pishinger Method')
disp('3 – Watson Method')
UserInput = input('Enter the Number corresponding to the selective Method and Press ENTER: ');
switch UserInput
  case 1 %calls a set of functions
  case 2 %calls a set of functions
  case 3 %calls a set of functions
  otherwise
    warning('PLEASE READ CAREFULLY!!');
    TF = true;
end

[Ferd]

Excellent! thanks!

Yeah, its cleaner. It just selects for only those specified numbers other numbers or characters are eliminated without specifying them.

Will have to include the switch function in the other User inputs I've coded...

Thanks again!

Answer 2

[Daniel Shub]

Why not get fancy:

UserInput = questdlg('Select a method.', 'Method List', ...
  'Aligrot', 'Pishinger', 'Watson', 'Aligrot')
switch lower(UserInput)
  case 'aligrot' %calls a set of functions
  case 'pishinger' %calls a set of functions
  case 'Watson' %calls a set of functions
end

[Ferd]

haha... Yea, will do...

[Ferd]

Whilst reading about the questdlg I also read inputdlg box and have added both in my code. Just a quick question, can we have an analog meter inputdialog box?

or I may be getting a bit too fancy...

[Walter Roberson]

What would you like an "analog meter inputdialog box" to look like?

[Image Analyst]

For more than 3 items, you can have a popup dialog box with a vertical array of buttons by using the menu() function. It returns the number of the button you clicked on and then you can check that button number with an if or switch statement.

[Ferd]

Basically, the way I set my equation in the code is that it can taken in a single value between 0.1 to 1. As of now, I simply use the "input" function to get the value. Is it possible to have an analog meter scroll bar that has limits from 0.1 to 1? So, the user can simply horizontally shift the pointer to what value is preferred instead of writing it in the command window?

Or would I have to create a GUI for it?

[Walter Roberson]

Everything in the graphics system is a GUI, including inputdialog. Some of the GUI are pre-written, that's all.

I do not recall any pre-written sliders at the moment, but sliders are not difficult to implement. You might want to check out (e.g.) "41 GUI examples" from the file exchange.

[Ferd]

Kewl thanks!