C ++接口編譯

Question

編輯：

我想出了解決方案。 我沒有在編譯指令中添加-combine，而是生成了錯誤。

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我正在研究Deitel和Deitel書《 C ++ How to Program》，並遇到了使用g ++構建和編譯C ++接口的問題。 問題是，我已經在.h文件中聲明了該類，並在.cpp文件中定義了實現，但是當我嘗試編譯編寫的測試文件時，我無法弄清楚如何使其能夠正常工作。 我收到的g ++錯誤是：

Undefined symbols:
  "GradeBook::GradeBook(std::basic_string<char, std::char_traits<char>, std::allocator<char> >)", referenced from:
      _main in ccohy7fS.o
      _main in ccohy7fS.o
  "GradeBook::getCourseName()", referenced from:
      _main in ccohy7fS.o
      _main in ccohy7fS.o
ld: symbol(s) not found
collect2: ld returned 1 exit status<

如果有人能指出我正確的方向，我將不勝感激。

我的頭文件：

//Gradebook 6 Header
//Purpose is to be the class declaration for the class Gradebook 6
//Declare public, privates, and function names. 

#include  //the standard c++ string class library
using std::string;

//define the class gradebook
class GradeBook
{
    public:  //all the public functions in the class

     GradeBook(string ); //constructor expects string input
     void setCourseName (string ); //method sets course name--needs string input
     string getCourseName(); //function returns a string value
     void displayMessage();  //to console

    private: //all private members of the class
        string courseName; 
}; //ends the class declaration 

我的.cpp文件是：

//Gradebook 6
// The actual implementation of the class delcaration in gradebook6.h

#include 
using std::cout;
using std::endl;

#include "gradebook6.h" //include the class definition

//define the class gradebook

GradeBook::GradeBook(string name) //constructor expects string input
{
    setCourseName(name); //call the set method and pass the input from the constructor. 
}

void GradeBook::setCourseName (string name) //method sets course name--needs string input
{
    courseName = name; //sets the private variable courseName to the value passed by name
}

string GradeBook::getCourseName() //function returns a string value
{
    return courseName;
}

void GradeBook::displayMessage()  //function does not return anything but displays //message to console
{
   cout //message here, the pre tag isn't letting it display
} //end function displayMessage

最后，我編寫了用於實現接口並對其進行測試的測試文件。

// Gradebook6 Test
// Program's purpose is to test our GradeBook5 header file and file seperated classes

#include 
using std::cout;
using std::endl;

#include "gradebook6.h" //including our gradebook header from the local file.

//being program
int main()
{
    //create two gradebook objects 
    GradeBook myGradeBook1 ("CSC 101 Intro to C++ Programming"); //create a default object using the default constructor
    GradeBook myGradeBook2 ("CSC 102 Data Structures in C++");

    //display intitial course name
    cout //another output message here that the code tag does not like

    return 0;
}

Answer 1

看起來您只需要在GradeBook.cpp對象文件中鏈接到最終的可執行文件即可。 想要發布您的Makefile或構建方式嗎？

Answer 2

您看到的是鏈接器錯誤（指示在“返回的ld”位中：ld是鏈接器）。 您需要將所有.cpp文件提供給g ++，以便它將進行編譯和鏈接，或者使用后者的-c開關從.cpp中創建一個.o，然后在另一個g ++命令上使用THAT .o進行構建（鏈接）可執行文件。