Arbitrary precision arithmetic system and calculator

http://isthe.com/chongo/tech/comp/calc/

Calc is an arbitrary precision C-like arithmetic system that is a

calculator, an algorithm-prototyper, and a mathematical research tool. Calc

comes with a rich set of built-in mathematical and programmatic functions.

Note: this copy of Calc is linked against the GNU Readline library and has

been converted to the ordinary GPL as per section 3 of the LGPL. See the

included calc-converted-to-gpl.txt document for details.