Extended-precision floating-point (##)

Extended-precision floating-point numbers are the basis of floating-point computation in PowerBASIC. The type-specifier character for an Extended-precision floating-point is: ##.

In PowerBASIC, arithmetic is optimized; it doesn't use Extended-precision unless it needs to. Extended-precision has been provided as a declarable data type, so that you can take advantage of its extra exponent range and precision if you wish.

Extended-precision values require 10 bytes of storage each. They have a range of approximately +/- 3.4*10^-4932 to 1.2*10^4932, and offer 18 digits of precision. All 18 digits can be "displayed" using the extended STR$ format (eg, STR$(var##,18)).

Extended-precision variables are identified by adding two Number symbols following a variable name (i.e., var##) or by using the DEFEXT statement.. You can also declare Extended-precision variables using the EXT or EXTENDED keywords with the DIM statement. For example:

DIM I AS EXT

DIM J AS EXTENDED

STR$ works with up to 16 significant digits (enough for a Double-precision value) by default. To get all 18 significant digits of an Extended-precision number in a string, use the enhanced STR$ function to specify 18 digits:

x$ = STR$(a##,18)

See Also

Array Data Types

Bit Data Types

Constants and Literals

Floating Point Data Types