sending an error message to the user

I am trying to write a code where the user is asked to input a value however the value must be (0<x<=0.25)how can I send the user a error message if they do not enter a value within the limits and allow them to attempt another input?

Answer 1

[KSSV]

function Hello(x)
if  ~(x >0 && x <= 0.25)
    error('input is not 0<x<=0.25')
end

[Sarah Chappell-Smith]

Hi I am still having a problem, the code keeps saying that there is an error and can not run. I'm sure I have entered something in correctly but am struggling to get the code to work.

clc
clear all
x=input('Enter the dimension of the x axis of the plate: ');
y=input('Enter the dimension of the y axid of the plate: ');
Fo=input('Enter a value for the Fourier Number: ')
function Hello(x)
if  ~(x >0 && x <= 0.25)
    error('input is not 0<x<=0.25')
end
end

[KSSV]

How you want to use the function? In the above no where you have called the function.

[Sarah Chappell-Smith]

I've managed to get it to work using;

while f0 <= 0 f0>0.25

 f0=input('Enter a value for the Fourier Number: ');

end

Answer 2

[Image Analyst]

Use errordlg() or helpdlg() wrapped inside a uiwait():

Try this snippet:

% Ask user for two floating point numbers.
defaultValue = {'45.67', '78.91'};
titleBar = 'Enter a value';
userPrompt = {'Enter floating point number 1 : ', 'Enter floating point number 2: '};
caUserInput = inputdlg(userPrompt, titleBar, 1, defaultValue);
if isempty(caUserInput),return,end; % Bail out if they clicked Cancel.
% Convert to floating point from string.
usersValue1 = str2double(caUserInput{1})
usersValue2 = str2double(caUserInput{2})
% Check for a valid number.
if isnan(usersValue1)
    % They didn't enter a number.  
    % They clicked Cancel, or entered a character, symbols, or something else not allowed.
  % Convert the default from a string and stick that into usersValue1.
    usersValue1 = str2double(defaultValue{1});
    message = sprintf('I said it had to be a number.\nTry replacing the user.\nI will use %.2f and continue.', usersValue1);
    uiwait(warndlg(message));
end
% Do the same for usersValue2