C++ 链接器错误 ("Linker command failed with exit code 1")

Question

我正在处理一个项目并不断收到链接器错误，即使到目前为止基本上没有可执行代码。错误消息如下，据我所知，它与我尚未定义的重载赋值运算符有关。

我可以通过私信进一步说明，或者如果你想看代码。这是因为我学校的学术诚信政策，我不希望被开除!

提前致谢!

---

调用:MacOS X C++ 链接器

g++ -o "ProjectName"./Class.o ./ProjectName.o
体系结构 x86_64 的 undefined symbol :

“Class::operator=(Class const&)”，引用自:

  Class::Class(Class const&) in Class.o

ld: 找不到架构 x86_64 的符号

clang:错误:链接器命令失败，退出代码为 1(使用 -v 查看调用)

make: *** [ProjectName] 错误 1

**更新**

如果您在任何地方看到“Class”作为类名，这意味着我忘记将它改回真实的类名，即 ShirtOrder。

这是我的主 cpp 文件中的代码:

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <cmath>
#include "ShirtOrder.h"

using namespace std;


/*********************************************************************************************************************
 ***************** FUNCTION PROTOTYPES -- FUNCTION PROTOTYPES -- FUNCTION PROTOTYPES -- FUNCTION PROTOTYPES **********
 *********************************************************************************************************************/

bool uploadFile(string fName, unsigned long &count, ShirtOrder* &head);
void clearLL(unsigned long &count, ShirtOrder* &head);
void summaryByMethod(unsigned long count, ShirtOrder* head);
void summaryByRegion(unsigned long count, ShirtOrder* head);

/*********************************************************************************************************************
 ***************** MAIN FUNCTION -- MAIN FUNCTION -- MAIN FUNCTION -- MAIN FUNCTION -- MAIN FUNCTION *****************
 *********************************************************************************************************************/

int main(int argc, char* argv[])
{
    if (argc < 2) // if only command line argument is program name
    {
        cout << "No file name entered." << endl;
    }

    else
    {
        ShirtOrder object;
        cout << "Test run" << endl;
    }
    return 0;
}

/**********************************************************************************************************
 ************ FUNCTION IMPLEMENTATIONS -- FUNCTION IMPLEMENTATIONS -- FUNCTION IMPLEMENTATIONS ************
 **********************************************************************************************************/

bool uploadFile(string fName, unsigned long &count, ShirtOrder* &head)
{
    return true;
}

void clearLL(unsigned long &count, ShirtOrder* &head)
{

}

void summaryByMethod(unsigned long count, ShirtOrder* head)
{

}

void summaryByRegion(unsigned long count, ShirtOrder* head)
{

}

我的 ShirtOrder.h 文件:

#ifndef SHIRTORDER_H_
#define SHIRTORDER_H_

#include <iostream>
#include <fstream>
#include <string>
#include <cmath>
#include <iomanip>

using namespace std;

class ShirtOrder
{
    friend ostream& operator<<(ostream &os, const ShirtOrder &rhsObj);

private:
    // the data members below are required (you may change identifiers)
    // there is no need for additional data members
    int orderYear, orderMonth, orderDay;
    char printMethod; // 's', 'i', or 'e'
    string message;
    int mediums; // number of medium shirts ordered
    int larges; // number of large shirts ordered
    int xls; // number of XL shirts ordered
    string shirtColor;
    string inkColor;
    string orderID;
    string region;
    string nameAndEmail;

    ShirtOrder* next; // new for P5

public:
    ShirtOrder(); // default constructor

    ShirtOrder(int orderYear, int orderMonth, int orderDay,
               char printMethod, string message, int mediums, int larges, int xls,
               string shirtColor, string inkColor, string orderID,
               string region, string nameAndEmail,
               ShirtOrder *soPtr = NULL);

    ShirtOrder(const ShirtOrder &otherObj);

    ~ShirtOrder(); // destructor                      // New for P5 (may not be in-line)

    ShirtOrder* getNext() const {return next;}        // New for P5 (may be in-line)

    void setNext(ShirtOrder* soPtr) {next = soPtr;}   // New for P5 (may be in-line)

    ShirtOrder operator=(const ShirtOrder &rhsObj);   // New for P5 (may not be in-line)

    double getBlankCost() const;
    double getPrintingCost() const;
    double getTotalCost() const;

    int    getLetterCount() const;
    char   getPrintMethod() const {return printMethod;}
    int    getOrderYear() const {return orderYear;}
    int    getOrderMonth() const {return orderMonth;}
    int    getOrderDay() const {return orderDay;}
    int    getMediums() const {return mediums;}
    int    getLarges() const {return larges;}
    int    getXls() const{return xls;}

    string getShirtColor() const {return shirtColor;}
    string getInkColor() const {return inkColor;}
    string getOrderID() const {return orderID;}
    string getRegion() const {return region;}
    string getNameAndEmail() const {return nameAndEmail;}
    string getMessage() const {return message;}

    void  setOrderYear (int orderYear) {this->orderYear = orderYear;}
    void  setOrderMonth (int orderMonth) {this->orderMonth = orderMonth;}
    void  setOrderDay (int orderDay) {this->orderDay = orderDay;}
    void  setPrintMethod (char printMethod) {this->printMethod = printMethod;}
    void  setMessage (string message) {this->message = message; }
    void  setMediums (int mediums) {this->mediums = mediums;}
    void  setLarges (int larges) {this->larges = larges;}
    void  setXls (int xls) {this->xls = xls;}
    void  setShirtColor (string shirtColor) {this->shirtColor = shirtColor;}
    void  setInkColor (string inkColor) {this->inkColor = inkColor;}
    void  setOrderID (string orderID) {this->orderID = orderID;}
    void  setRegion (string region) {this->region = region;}
    void  setNameAndEmail (string nameAndEmail) {this->nameAndEmail = nameAndEmail;}

}; // end declaration of class ShirtOrder

/******************************************************************************************
 *********** MEMBER FUNCTION IMPLEMENTATIONS -- MEMBER FUNCTION IMPLEMENTATIONS ***********
 ******************************************************************************************/

#endif /* SHIRTORDER_H_ */

我的 ShirtOrder.cpp 文件:

#include "ShirtOrder.h"
#include <iostream>
#include <string>
#include <fstream>
#include <vector>

using namespace std;

/******************************************************************************************
 *********** MEMBER FUNCTION IMPLEMENTATIONS -- MEMBER FUNCTION IMPLEMENTATIONS ***********
 ******************************************************************************************/

// Default Constructor
ShirtOrder::ShirtOrder()
{
    orderYear = 0;
    orderMonth = 0;
    orderDay = 0;
    printMethod = 'x'; // 's', 'i', or 'e'
    message = "";
    mediums = 0; // number of medium shirts ordered
    larges = 0; // number of large shirts ordered
    xls = 0; // number of XL shirts ordered
    shirtColor = "";
    inkColor = "";
    orderID = "";
    region = "";
    nameAndEmail = "";

    next = NULL;

    cout << "Default constructor has run" << endl;
}

// Other Constructor
ShirtOrder::ShirtOrder(int orderYear, int orderMonth, int orderDay,
        char printMethod, string message, int mediums, int larges, int xls,
        string shirtColor, string inkColor, string orderID,
        string region, string nameAndEmail, ShirtOrder *soPtr)
{
    this-> orderYear = orderYear;
    this->orderMonth = orderMonth;
    this->orderDay = orderDay;
    this->printMethod = printMethod; // 's', 'i', or 'e'
    this->message = message;
    this->mediums = mediums; // number of medium shirts ordered
    this->larges = larges; // number of large shirts ordered
    this->xls = xls; // number of XL shirts ordered
    this->shirtColor = shirtColor;
    this->inkColor = inkColor;
    this->orderID = orderID;
    this->region = region;
    this->nameAndEmail = nameAndEmail;

    next = NULL;

    cout << "Constructor Numero Dos has run" << endl;
}

// Other, other constructor
ShirtOrder::ShirtOrder(const ShirtOrder &otherObj)
{
    ShirtOrder object;
    object = otherObj;
    object.orderYear = otherObj.orderYear;
    object.orderMonth = otherObj.orderMonth;
    object.orderDay = otherObj.orderDay;
    object.printMethod = otherObj.printMethod;
    object.message = otherObj.message;
    object.mediums = otherObj.mediums;
    object.larges = otherObj.larges;
    object.xls = otherObj.xls;
    object.shirtColor = otherObj.shirtColor;
    object.inkColor = otherObj.inkColor;
    object.orderID = otherObj.orderID;
    object.region = otherObj.region;
    object.nameAndEmail = otherObj.nameAndEmail;
    object.next = otherObj.next;

    cout << "Constructor Numero Tres has run" << endl;
}

// DESTRUCTOR
ShirtOrder::~ShirtOrder()
{
    cout << "Destructor has run" << endl;
}

ShirtOrder operator=(const ShirtOrder &rhsObj)
{

}

// COME BACK TO REMOVE WHITESPACE
int ShirtOrder::getLetterCount() const
{
    string tempMessage = getMessage();

    int pos1 = tempMessage.find("\"") + 1; // find first occurrence of a double quotation mark and assign position +1 value to pos1
    int pos2 = tempMessage.rfind("\"") - 1; // find last occurrence of a double quotation mark and assign position -1 value to pos2

    tempMessage = tempMessage.substr(pos1, (pos2 - pos1)); // sets variable tempMessage to string between quotation marks

    return tempMessage.length();
}

double ShirtOrder::getBlankCost() const
{
    return 0.0;
}

double ShirtOrder::getPrintingCost() const
{
    return 0.0;
}

double ShirtOrder::getTotalCost() const
{
    return 0.0;
}

Answer 1

链接器告诉您您的 Class.cpp 中缺少 Class::Class(Class const&)

您需要从您的 Class.h 中删除它的声明或在您的 Class.cpp 中添加实现。

您最初报告的错误与代码不匹配。无论如何，这些是您遇到的问题:

• 赋值运算符返回错误:ShirtOrder operator=(const ShirtOrder &rhsObj)(应为 ShirtOrder&)
• operator=的实现是空的，你应该分配成员然后返回*this;
• 您的 operator= 定义为 ShirtOrder& ShirtOrder::operator=(const ShirtOrder &rhsObj)，而在 .cpp 文件中它必须是这样的:ShirtOrder& ShirtOrder::operator=(const ShirtOrder &rhsObj)
• 您的复制构造函数 ShirtOrder::ShirtOrder(const ShirtOrder &otherObj) 没有正确的实现。它必须将所有这些值分配给 this-> 而不是 object.