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我编了一个小程序，想演示一下对于static成员直接使用类调用，结果出错：
Generating Code...
Linking...
Data.obj : error LNK2001: unresolved external symbol "private: static int CData::B" (?B@CData@@0HA)
Data.obj : error LNK2001: unresolved external symbol "private: static int CData::A" (?A@CData@@0HA)
Data.obj : error LNK2001: unresolved external symbol "private: static int CData::C" (?C@CData@@0HA)
Release/test2.exe : fatal error LNK1120: 3 unresolved externals
Error executing link.exe.
test2.exe - 4 error(s), 0 warning(s)
代码如下：
// Data.h: interface for the CData class.
//
//////////////////////////////////////////////////////////////////////
#if !defined DATA_H
#define DATA_H
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
class CData
{
public:
static void Print();
static void Add();
static void Set(int i, int j);
CData();
virtual ~CData();
private:
static int A;
static int B;
static int C;
};
#endif // !defined(AFX_DATA_H__330778C5_0D94_4045_B715_60ABDDB71B7F__INCLUDED_)
// Data.cpp: implementation of the CData class.
//
//////////////////////////////////////////////////////////////////////
#include "stdafx.h"
#include "Data.h"
#include "stdio.h"
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
CData::CData()
{
}
CData::~CData()
{
}
void CData::Set(int i, int j)
{
A = i;
B = j;
}
void CData::Add()
{
C = A + B;
}
void CData::Print()
{
printf("%d\n", C);
}
// test2.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "data.h"
int main(int argc, char* argv[])
{
// test2.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "data.h"
int main(int argc, char* argv[])
{
CData::Set(4, 5);
CData::Add();
CData::Print();
return 0;
}// test2.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "data.h"
int main(int argc, char* argv[])
{
CData::Set(4, 5);
CData::Add();
CData::Print();
return 0;
}// test2.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "data.h"
int main(int argc, char* argv[])
{
CData::Set(4, 5);
CData::Add();
CData::Print();
return 0;
}
(佚名)
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在Data.h中定义的静态变量必须在Data.cpp中进行初始化，即使成员定义的是私有的。在Data.cpp中添加：
int CData::A = 0;
int CData::B = 0;
int CData::C = 0;
此问题由李海回答。
附加关键字：编程, 源程序, programming, source code, C/C++, MFC, C++ Builder, Borland C++, Turbo C, C, BCB, 错误信息, error, error message, link, compile, runtime。
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LNK2001: unresolved external symbol "private: static int CData::B" (?B@CData@@0HA)