Why am I coming up with an undefined function or variable on this simple temperature script?

I'm writing a very simple temperature conversion script, and keep getting the undefined error. Here is the script:

function[y] = temp_conversion(x,unit) 
if strcmp(unit,'Farenheit'); 
   y = (x - 32)*(5/9); 
elseif strcmp(unit,'Centigrade'); 
   y = (x * (9/5)) + 32; 
end

When I call it in matlab using

[y] = temp_conversion(25,Farenheit)

or [y] = temp_conversion(25,Centigrade)

I will get

"undefined function or variable 'Farenheit'." or "undefined function or variable 'Centigrade'." respectively.

I feel like I am missing something very simple, and am looking for some guidance, hope to hear from you guys.

Answer 1

[Image Analyst]

Try passing in a string.

temp_conversion(25, 'Farenheit')

and for robustness, use strcmpi() instead of strcmp().

[Image Analyst]

To make it even more robust, just check the first character, in case people misspell it or pass in the official units name of 'Celsius' instead of Centigrade, and check for illegal units:

function y = temp_conversion(x,unit) 
try
  if upper(unit(1)) == 'F' 
     y = (x - 32)*(5/9); 
  elseif upper(unit(1)) == 'C' 
     y = (x * (9/5)) + 32; 
  else
     warningMessage = sprintf('Error: %s is an unknown unit', unit);
     uiwait(warndlg(warningMessage));
     y = [];
  end
catch ME
  errorMessage = sprintf('Error in function %s() at line %d.\n\nError Message:\n%s', ...
  ME.stack(1).name, ME.stack(1).line, ME.message);
  fprintf(1, '%s\n', errorMessage);
  uiwait(warndlg(errorMessage));
end

[Adli]

Of course! Seems so obvious now. Thank you IA, I think you just saved me a lot of stress in the future as well.