Correct use of isempty

Hi all,

I am making a program that can degrees to radiens and vice versa. I'd like to know if I can use the isempty function in the manner below. If I have used it incorrectly, I would appreciate if you could tell me how to use it in the right manner.

I would also like some help with the switch case statement. I would like the user to input a 2 letter code to determine if he is to convert degrees to radients or radients to degrees (DR or RD). However the code cannot run , I would like to know how to solve my problem.

clc
prompt = 'Convert Degree to Radients or Radient to Degree?';
option = input(prompt, 's')
switch option
    case DR
        angleD=input('Enter angle in degrees');
        if not isempty(angleD)
            rad=degrees * pi / 180
            x=fprintf('The angle is equal to %f radients',rad);
            disp(x)
    case RD 
        angleR=input('Enter angle in radients');
        if not isempty(angleR)
            deg=radians * 180 / pi
            y=fprintf('The angle is %f degrees',deg);
    otherwise
        disp('invalid option')
end

P.S I am using octave online

Answer 1

[Walter Roberson]

clc
prompt = 'Convert Degree to Radients or Radient to Degree?';
option = input(prompt, 's')
switch option
    case 'DR'
        angleD=input('Enter angle in degrees');
        if ~isempty(angleD)
            rad=degrees * pi / 180
            x=fprintf('The angle is equal to %f radients',rad);
            disp(x)
    case 'RD' 
        angleR=input('Enter angle in radients');
        if ~isempty(angleR)
            deg=radians * 180 / pi
            y=fprintf('The angle is %f degrees',deg);
    otherwise
        disp('invalid option')
end