Using BigInt class in Visual C++ 2008 Express

I need to use the bigint class in visual c++ 2008 express edition. I am currently getting these error messages when compiling

    1>------ Build started: Project: P Root Test, Configuration: Debug Win32 ------
    1>Linking...
    1>P Root Test.obj : error LNK2019: unresolved external symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class BigInteger const &)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@ABVBigInteger@@@Z) referenced in function _main
    1>P Root Test.obj : error LNK2019: unresolved external symbol "public: void 开发者_Python百科__thiscall BigInteger::operator=(class BigInteger const &)" (??4BigInteger@@QAEXABV0@@Z) referenced in function _main
    1>P Root Test.obj : error LNK2019: unresolved external symbol "public: __thiscall BigInteger::BigInteger(int)" (??0BigInteger@@QAE@H@Z) referenced in function _main
    1>P Root Test.obj : error LNK2019: unresolved external symbol "public: void __thiscall BigInteger::multiply(class BigInteger const &,class BigInteger const &)" (?multiply@BigInteger@@QAEXABV1@0@Z) referenced in function "public: class BigInteger __thiscall BigInteger::operator*(class BigInteger const &)const " (??DBigInteger@@QBE?AV0@ABV0@@Z)
    1>G:\My Stuff\# School\Crypto\P Root Test\Debug\P Root Test.exe : fatal error LNK1120: 4 unresolved externals
    1>Build log was saved at "file://g:\My Stuff\# School\Crypto\P Root Test\P Root Test\Debug\BuildLog.htm"
    1>P Root Test - 5 error(s), 0 warning(s)
    ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Have you checked the library which defined the BigInteger in your project?