LNK2019：函数"函数"中'symbol'引用未解析的外部符号;致命错误 LNK1120：1 未解析的外部

嗨，我做了一个简单的C++程序，但我遇到了错误，我不知道我做错了什么。我是C++语法的新手，所以我不知道我犯了什么错误导致了所述的链接器错误。以下是生成此错误的示例代码：

ITest.h

#ifndef ITest_H
#define ITest_H
//#[ ignore
#ifdef _MSC_VER
// disable Microsoft compiler warning (debug information truncated)
#pragma warning(disable: 4786)
#endif
//#]
//## auto_generated
#include <string>
//## auto_generated
#include <algorithm>
//## auto_generated
//## link itsNmNeighborhoodEntry
class NmNeighborhoodEntry;
//## class ITest
class ITest {
//#[ ignore
    ////    Constructors and destructors    ////
public :
    //## auto_generated
    virtual ~ITest();
    ////    Relations and components    ////
protected :
    NmNeighborhoodEntry* itsNmNeighborhoodEntry;        //## link itsNmNeighborhoodEntry
};
#endif

ITest.cpp

//## auto_generated
#include "ITest.h"
//## link itsNmNeighborhoodEntry
#include "NmNeighborhoodEntry.h"
//## class ITest
ITest::~ITest() {
}

测试1.h

#ifndef Test1_H
#define Test1_H
//#[ ignore
#ifdef _MSC_VER
// disable Microsoft compiler warning (debug information truncated)
#pragma warning(disable: 4786)
#endif
//#]
//## auto_generated
#include <string>
//## auto_generated
#include <algorithm>
//## class Test1
#include "ITest.h"
//## auto_generated
class NmNeighborhoodEntry;
//## class Test1
class Test1 : public ITest {
//#[ ignore
    // Default Constructor is Private
    public:
       Test1();

    // Default Copy Constructor is Private
    private:
       Test1(const Test1& self);

    // Default Assignment Operator is Private
    private:
       Test1& operator=(const Test1& aTest1);
//#]
    ////    Constructors and destructors    ////
public :
    //## auto_generated
    ~Test1();
    NmNeighborhoodEntry* getNmNeighborhoodEntry();
};
#endif

Test1.cpp

//## auto_generated
#include "Test1.h"
//## auto_generated
#include "NmNeighborhoodEntry.h"
NmNeighborhoodEntry* itsNmNeighborhoodEntry;
//## class Test1
Test1::~Test1() {
}
Test1::Test1() {
}

NmNeighborhoodEntry* getNmNeighborhoodEntry() { 
    //return itsNmNeighborhoodEntry;
    return NULL;
}

NmNeighborhoodEntry.h

#ifndef NmNeighborhoodEntry_H
#define NmNeighborhoodEntry_H
//#[ ignore
#ifdef _MSC_VER
// disable Microsoft compiler warning (debug information truncated)
#pragma warning(disable: 4786)
#endif
//#]
//## auto_generated
#include <string>
//## auto_generated
#include <algorithm>
//## class NmNeighborhoodEntry
class NmNeighborhoodEntry {
//#[ ignore
    // Default Constructor is Private
    private:
       NmNeighborhoodEntry();

    // Default Copy Constructor is Private
    private:
       NmNeighborhoodEntry(const NmNeighborhoodEntry& self);

    // Default Assignment Operator is Private
    private:
       NmNeighborhoodEntry& operator=(const NmNeighborhoodEntry& aNmNeighborhoodEntry);
//#]
    ////    Constructors and destructors    ////
public :
    //## auto_generated
    ~NmNeighborhoodEntry();
    bool myIsPending;       //## attribute myIsPending
    unsigned short index;       //## attribute myNodeIndex
};
#endif

NmNeighborhoodEntry.cpp

//## auto_generated
#include "NmNeighborhoodEntry.h"
//## class NmNeighborhoodEntry
NmNeighborhoodEntry::~NmNeighborhoodEntry() {
}

驱动程序.cpp

//#include "ITest.h"
#include "Test1.h"
//#include "Test2.h"
#include "NmNeighborhoodEntry.h"
Test1 *test1;
//Test2 *test2;
NmNeighborhoodEntry* myNmNeighborhoodEntry;
void main() {
    test1 = new Test1;
    //test2 = new Test2;
    //test1->itsNmNeighborhoodEntry = NULL;
    myNmNeighborhoodEntry = test1->getNmNeighborhoodEntry();
}