Turbo Basic Data Types

                  Declaration
 Type             Character *       Range       Accuracy       Storage
 Integer               %      -32768 to 32767   Perfect        2 bytes
 Long integer          &      -2E31 to 2E31     Perfect        4 bytes
 Single precision      !      10E-38 to 10E38   6 digits       4 bytes
 Double precision      #      10D-38 to 10D38   16 digits      8 bytes
 String                $

 * Variables may also be typed by means of DEFtype statements:
   DEFINT, DEFLNG, DEFSNG, DEFDBL, and DEFSTR. Variables that are not
   explicitly typed are treated as single precision.

 String storage: 4 bytes for descriptor, 1 byte for string back pointer,
                 and 1 byte for each character in the string.