Thread: Unresolved External In Class In VC++ 2008

I am trying to write a new class for performing some functions.
Basically I am writing a ECC math class.

I declared a variable as :

ECC a;
a.InitEllipticCurve(a, b, prime); //This is where i get the Unresolved external.

I've included the ECC.h file..

Here is the error :

1>Source.obj : error LNK2019: unresolved external symbol "public: void __thiscall ECC::InitEllipticCurve(__int64,__int64,__int64)" (?InitEllipticCurve@ECC@@QAEX_J00@Z) referenced in function _main

I am new to C++ & I cant understand the reason of this error, which I think is a linker error.

Best Regards
KKR