switch case construction help

(Ajay deleted the question so I (MF) am restoring it as best I can.)

I wrote this body of code:

function output = InteriorAngle(input)

switch input (InteriorAngle)

case 'triangle'

disp ('180')

case 'square'

disp ('360');

case 'pentagon'

disp ('540');

case 'hexagon'

disp ('720');

case 'heptagon'

disp ('900');

case 'octagon'

disp ('1080');

case 'nonagon'

disp ('1260');

case 'decagon'

disp ('1440');

otherwise

disp ('0');

end

end

but for some reason, it's not running when i input,

in = cell(1,3);

in{1,1} = 'triangle';

in{1,2} = 'hexagon';

in{1,3} = 'dodecagon';

out = InteriorAngle(in)

what am i doing wrong?

[Daniel Shub]

Not running is not a helpful description. What error do you get? When I run it I get an error about recursive limit being reached. Do you understand why your function is recursively calling itself?

[Ajay]

Undefined function or variable 'K'.

Error in InteriorAngle (line 2) switch in{K}

Error in Lab05 (line 12) out = InteriorAngle(in)

^Those are the errors I'm getting, so I don't get an error on the recursive limit being reached?

[Daniel Shub]

Then you are not running the posted code since line 2 of the InteriorAngle function you posted is not "switch in{K}".

[Daniel Shub]

Okay, I can reproduce the error with your new code. The error suggests that K is used on line 2 (which you can see it is), but that it is not defined before that. Since it is the 2nd line, it is pretty obvious that you have not defined K. You are also going to have a problem with "in" being undefined also. These errors are picked up by mlint, and you should pay attention to them.

[Ajay]

Okay, so now with the above edit, i'm getting that the Maximum recursion limit of 500 reached. why is this happening?

[Daniel Shub]

Look back at my first comment...

[Walter Roberson]

Question content has been edited out of existence by the original poster :(

[Matt Fig]

Saved from google cache:

I wrote this body of code:

function output = InteriorAngle(input)

switch input (InteriorAngle)

case 'triangle'

disp ('180')

case 'square'

disp ('360');

case 'pentagon'

disp ('540');

case 'hexagon'

disp ('720');

case 'heptagon'

disp ('900');

case 'octagon'

disp ('1080');

case 'nonagon'

disp ('1260');

case 'decagon'

disp ('1440');

otherwise

disp ('0');

end

end

but for some reason, it's not running when i input,

in = cell(1,3);

in{1,1} = 'triangle';

in{1,2} = 'hexagon';

in{1,3} = 'dodecagon';

out = InteriorAngle(in)

what am i doing wrong?

Answer 1

[Matt Fig]

You are recursively calling the function from inside the function with no way to terminate the recursion. Additionally, you have named a variable the same name as a MATLAB function (INPUT). In general, you should avoid this practice as it masks the function.

Once you take care of these problems, put your switch inside a FOR loop that loops over the length of the input argument. You switch on IN{ii}.

[Ajay]

i tried doing that, but i'm getting "Index exceeds matrix dimensions"

[Matt Fig]

Show your new code in a comment below, please.

[Ajay]

function output = InteriorAngle(input)
  for s=1:8,
  switch input ('s')
      case 'triangle'
             disp ('180')
      case 'square'
              disp ('360');
      case 'pentagon'
              disp ('540');
      case 'hexagon'
              disp ('720');
      case 'heptagon'
              disp ('900');
      case 'octagon'
              disp ('1080');
      case 'nonagon'
              disp ('1260');
      case 'decagon'
              disp ('1440');
      otherwise
              disp ('0');
  end
  end
  end

[Matt Fig]

Why is s always 1-through-8? What if the length of input is only 3 as in your example?

for ii = 1:length(IN)  

switch IN{ii}

Answer 2

[Ajay]

it worked and i get it, thanks!