Question

好的，所以我几个月没有使用过C ++，而我的一个问题一直是使用多个标题。目前我的问题是所有类的标题都链接到.cpp文件使用的主标题。我正在使用ifndef来确保没有重复，但我认为问题是当一组文件由于我的构建输出而被编译时

1>  student.cpp
1>  person.cpp
1>  main.cpp
1>  functions.cpp
1>  faculty.cpp
1>  Generating Code...
1>functions.obj : error LNK2005: "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct Address)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@UAddress@@@Z) already defined in faculty.obj
1>functions.obj : error LNK2005: "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct Name)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@UName@@@Z) already defined in faculty.obj
1>main.obj : error LNK2005: "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct Address)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@UAddress@@@Z) already defined in faculty.obj
1>main.obj : error LNK2005: "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct Name)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@UName@@@Z) already defined in faculty.obj
1>person.obj : error LNK2005: "class std::basic_ostream<char,struct std::char_traits<char>     > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct Address)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@UAddress@@@Z) already defined in faculty.obj
1>person.obj : error LNK2005: "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct Name)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@UName@@@Z) already defined in faculty.obj
1>student.obj : error LNK2005: "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct Address)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@UAddress@@@Z) already defined in faculty.obj
1>student.obj : error LNK2005: "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct Name)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@UName@@@Z) already defined in faculty.obj
1>C:\Users\Fluzzarn\Documents\Visual Studio 2012\Projects\pa1\Debug\pa1.exe : fatal error LNK1169: one or more multiply defined symbols found
1>
1>Build FAILED.
1>
1>Time Elapsed 00:00:02.24

所有cpp文件只包含我的“header.h”，它本身包含所有其他标题。

Header.h：

#ifndef HEADER_H
#define HEADER_H


#include "person.h"
#include "faculty.h"
#include "student.h"
#include <iostream>
#include <fstream>
#include <list>
#include <sstream>
using namespace std;

bool searchForUser();
void loadFromFile(std::string fileName, std::list<Person> targetList);
void loadBasicInfo(std::fstream& fileReader,Person tempPerson);

#endif

我一直在努力解决这个问题超过一个小时，任何见解都会受到赞赏

编辑：

重载＆lt;＆lt;

std::ostream& operator<<(std::ostream& os,const Address ad)
{
    os << ad.mStreetAddress << std::endl;
    os << ad.mCity << " , " << ad.mState << std::endl;
    os << ad.mZip;

    return os;

};

地址是结构

Answer 1

您将函数定义放在.cpp文件中，就像评论所说的那样。为了防止“找不到运算符” - 错误，你必须在头文件中保留函数声明：

 std::ostream& operator<<(std::ostream& os,const Address ad);

不要忘记行尾的分号。请注意，声明只包含函数头，而且没有正文。

你应该传递ad作为参考，但这只是一个小细节，与你的问题无关。

每个.cpp创建两个LNK2005错误

1 个答案: