error LNK2001: unresolved external symbol "void __cdecl test5(int)

You need to add the library to the linker options : go to your project settings, then the linker settings, and add the .lib file there.

Thx for reply, the point is I dont know which .lib file need to be added, there is no .lib files included in the documents.

Ah, apparently it's not

Ah, apparently it's not a proper library. This is from their docs :

"You will need to compile newran.cpp, myexcept.cpp and extreal.cpp and link the resulting object files to your programs. Your source files which access newran will need to have newran.h as an include file."

So, do exactly that : include the mentioned.cpp and .h files in your project, and rebuild all.

I did what you said, include all the three .cpps and those .hs in the project, rebuild it, then got the follow errors:

--------------------Configuration: tryrand - Win32 Debug--------------------
Compiling...
tryrand.cpp
h:\newran02\myexcept.cpp(68) : error C2065: 'strlen' : undeclared identifier
h:\newran02\myexcept.cpp(69) : error C2065: 'strcpy' : undeclared identifier
h:\newran02\myexcept.cpp(72) : error C2065: 'strncpy' : undeclared identifier
h:\newran02\newran.cpp(351) : error C2065: 'fabs' : undeclared identifier
h:\newran02\newran.cpp(351) : error C2065: 'exp' : undeclared identifier
h:\newran02\newran.cpp(354) : error C2065: 'sqrt' : undeclared identifier
h:\newran02\newran.cpp(397) : error C2065: 'pow' : undeclared identifier
h:\newran02\newran.cpp(415) : error C2065: 'log' : undeclared identifier
h:\newran02\newran.cpp(420) : error C2065: 'floor' : undeclared identifier
h:\newran02\newran.cpp(607) : error C2065: 'sin' : undeclared identifier
extreal.cpp
myexcept.cpp
newran.cpp
Error executing cl.exe.

tryrand.exe - 10 error(s), 0 warning(s)

thx for ur help so far, but plz help me fix this as well..

wait a sec.....i include math.h and string.h in the project and the above problem is gone, instead,

--------------------Configuration: tryrand - Win32 Debug--------------------
Linking...
extreal.obj : error LNK2005: "public: class ExtReal __thiscall ExtReal::operator+(class ExtReal const &)const " (??HExtReal@@QBE?AV0@ABV0@@Z) already defined in tryrand.obj
extreal.obj : error LNK2005: "public: class ExtReal __thiscall ExtReal::operator-(class ExtReal const &)const " (??GExtReal@@QBE?AV0@ABV0@@Z) already defined in tryrand.obj
extreal.obj : error LNK2005: "public: class ExtReal __thiscall ExtReal::operator*(class ExtReal const &)const " (??DExtReal@@QBE?AV0@ABV0@@Z) already defined in tryrand.obj
extreal.obj : error LNK2005: "public: class ExtReal __thiscall ExtReal::operator-(void)const " (??GExtReal@@QBE?AV0@XZ) already defined in tryrand.obj
extreal.obj : error LNK2005: "class ostream & __cdecl operator<<(class ostream &,class ExtReal const &)" (??6@YAAAVostream@@AAV0@ABVExtReal@@@Z) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: __thiscall Exception::Exception(char const *)" (??0Exception@@QAE@PBD@Z) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: static void __cdecl Exception::AddMessage(char const *)" (?AddMessage@Exception@@SAXPBD@Z) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: static void __cdecl Exception::AddInt(int)" (?AddInt@Exception@@SAXH@Z) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: static void __cdecl Tracer::PrintTrace(void)" (?PrintTrace@Tracer@@SAXXZ) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: static void __cdecl Tracer::AddTrace(void)" (?AddTrace@Tracer@@SAXXZ) already defined in tryrand.obj
myexcept.obj : error LNK2005: "void __cdecl Terminate(void)" (?Terminate@@YAXXZ) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: __thiscall Logic_error::Logic_error(char const *)" (??0Logic_error@@QAE@PBD@Z) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: __thiscall Runtime_error::Runtime_error(char const *)" (??0Runtime_error@@QAE@PBD@Z) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: __thiscall Domain_error::Domain_error(char const *)" (??0Domain_error@@QAE@PBD@Z) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: __thiscall Invalid_argument::Invalid_argument(char const *)" (??0Invalid_argument@@QAE@PBD@Z) already defined in tryrand.obj
myexcept.obj : error LNK2005: "public: __thiscall Length_error::Length_error(char const *)" (??0Length_error@@QAE@PBD@Z) already defined in tryrand.obj

tryrand.exe - 193 error(s), 0 warning(s)

another 193 errors comes out.....

I did what u said and the errors are all gone, except when I excute the program , a window pops up and says "debug error: abnormal program termination".....but anyway, thx for your help infinity08 :)

>> a window pops up and says "debug error: abnormal program termination"

That's an error in the code. Either the library contains a bug, or your code does.