How to break a function if the user input is not a number?

I am writing a code to let the user enter the input multiple times using a while loop as shown below:

time=input('Pls enter the time: ');
if isnumeric(time);
    while (1)
        if time<120;
        disp('Stage 1')
        time=input('Pls enter the time: ');
    elseif time<250;
        disp('Stage 2')
        time=input('Pls enter the time: ');
    elseif time>=250;
        disp('Free Flight')
        time=input('Pls enter the time: ');
        end
    end
else
    disp('you did not enter a number')
end

I want the code to terminate the program when the user input is not a number. How do I achieve this? The isnumeric does not work in this case.

EDIT:

The basic idea is:

1. Prompt the user to enter a number input so that it returns 'Stage 1' when the input is <120; 'Stage 2' when the input is <250 and 'Stage 3' if the input is >250.

2. After the user entered a valid input, the code will prompt the user to enter another input such that the loop will continue until the user entered an invalid input (i.e. a non-numbered input)

3. The code must break once the user entered a non-number (e.g. hello, abc, #@% etc.) Currently my code above will prompt the user to enter another input after he/she entered a non-number. Which is not what I wanted.

Thanks.

[Matt J]

Clarify what you mean by "isnumeric does not work in this case". What case is that? For what value of 'time' did it fail?

[David C.]

Using my current code, the program will prompt the user to enter another input when he first entered a non-number (e.g. hello). I do not want this. I need the program to break when a non-number is entered.

Thanks.

Answer 1

[Matt J]

time=input('Pls enter the time: ');
if isnumeric(time);
    while isnumeric(time)
        if time<120;
         disp('Stage 1')

          elseif time<250;
           disp('Stage 2')

          elseif time>=250;
           disp('Free Flight')

          end

       time=input('Pls enter the time: ');
      end
  else
      disp('you did not enter a number')
  end

Answer 2

[Image Analyst]

Try this code. It's pretty robust:

defaultValue = '12:34';
titleBar = 'Enter the time';
userPrompt = 'Enter the time';
loopCounter = 1;
failSafeMaxNumberOfLoops = 20;  % Fail safe to prevent permanent loops.
while loopCounter < failSafeMaxNumberOfLoops
  % Ask user for a number.
  caUserInput = inputdlg(userPrompt, titleBar, 1, {num2str(defaultValue)});
  if isempty(caUserInput),return,end; % Bail out if they clicked Cancel.
  numericValue = str2double(char(caUserInput));
  if ~isnan(numericValue) && ~isempty(numericValue)
    % It's all numbers.
    break;
  end
  % If it gets to here, it's not all numbers.
  % Optionally warn them.  COmment out if you don't want the warning.
  warningMessage = sprintf('No!\n%s is not all numbers!', char(caUserInput));
  uiwait(warndlg(warningMessage));
  % Prevent run away loops
  loopCounter = loopCounter + 1;
end
if loopCounter < failSafeMaxNumberOfLoops
  message = sprintf('Success!\nThe number is %f', numericValue);
  fprintf('The number is %f', message);
  msgbox(message);
else
  warningMessage = sprintf('I give up.\nApparently you do not want to cooperate!');
  uiwait(warndlg(warningMessage));
end