MATLAB: Using inputdlg and isnan

inputdlgisnanstr2num

I need a user input using inputdlg, I need it to be a number and I need it to keep assking until I get a number. So far, it just gets stuck in a loop.

Please help, this should be easy!

nof=inputdlg('Enter number of floors:');
NOF=str2double(nof);    
while isempty(NOF)||isnan(NOF)
        disp('error')
        nof=inputdlg('Enter number of floors:');
        uiwait;
end

Best Answer

In your code, NOF never changes inside the loop. Therefore, if the loop enters, it won't ever exit because the exit condition will never be true. Make sure you are calling str2double within the loop:

res=inputdlg('Enter number of floors:');
nof=str2double(res);
while isempty(res) || isnan(nof)
    %  ^ user canceled   ^ input was not numeric
    disp('error')
    res=inputdlg('Enter number of floors:');
    nof=str2double(res);
end

If you want to let the user use the command line:

opts.WindowStyle = 'normal';
res=inputdlg('Enter number of floors:', '', 1, {''}, opts);
nof=str2double(res);
while isempty(res) || isnan(nof)
    disp('error')
    res=inputdlg('Enter number of floors:', '', 1, {''}, opts);
    nof=str2double(res);
end

Related Solutions

MATLAB: How to use inputdlg in a for loop to return a numerical array

A few good practice tips:

avoid i and j as variable names to avoid confusion with sqrt(-1), avoid l (lowercase L) as well to avoid confusion with the numeral 1.
put all code that does not depend on your loop index outside of your loop so it is executed only once
don't use variable name like sum or length, as that will prevent you from using the internal functions with that name (this is called 'shadowing' of a function)
pay attention to the warnings mlint is giving you, try to resolve all warnings. If you are certain the warning doesn't apply in your case (which is rare), right-click the orange line and select the 'suppress warning on this line' option.

So here is your code with those tips applied:

n_floors=inputdlg('enter number of floors: ');
n_floors=str2double(n_floors);
dimensions={'Enter height','Enter width:','Enter length:'};
dlgtitle='Dimensions';
dims=[1 35];
height=zeros(1,n_floors);
width=zeros(1,n_floors);
len=zeros(1,n_floors);%you could consider depth as a variable name
for floor=1:n_floors
    answer=inputdlg(dimensions,dlgtitle,dims);
    height(floor)=str2double(answer{1});
    width(floor)=str2double(answer{2});
    len(floor)=str2double(answer{3});
end

MATLAB: How to make sure variables aren’t overwritten in loops

I suggest you load up rows in a table. See documentation for the table() function.

Best Answer

Related Solutions

MATLAB: How to use inputdlg in a for loop to return a numerical array

MATLAB: How to make sure variables aren’t overwritten in loops

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