Task

 verify the version/revision of your currently running (compiler/interpreter/byte-compiler/runtime environment/whatever your language uses) and exit if it is too old.
 check whether the variable "bloop" exists and whether the math-function "abs()" is available and if yes compute abs(bloop).


Extra credit

 Report the number of integer variables in global scope, and their sum.


   % convert version into numerical value
   v = version; 
   v(v=='.')=' ';
   v = str2num(v); 
   if v(2)>10; v(2) = v(2)/10; end; 
   ver = v(1)+v(2)/10; 
   if exist('OCTAVE_VERSION','builtin')
      if ver < 3.0, 
         exit
      end; 
   else
      if ver < 7.0, 
         exit
      end; 
   end	
 
   % test variable bloob, and test whether function abs is defined as m-function, mex-function or builtin-function
   if exist('bloob','var') && any(exist('abs')==[2,3,5])
	printf('abs(bloob) is %f\n',abs(bloob));
	return; 
   end; 