A lightweight C++ class for arbitrary precision arithmetic. You should use a compiler that supports C++11. VC++2010/VC++2012 and the latest gcc/mingw are capable of compiling this.
Output of the sample program:
integer1: 222222222222222222222222222222222222222222222222222222222222222222222
integer2: 444444444444444444444444444444444444444444444444444444444444444444444
integer3 (integer1 * integer2): 98765432098765432098765432098765432098765432098765432098765432098765234567901234567901234567901234567901234567901234567901234567901234568