c ++未定义对vtable的引用 [英] c++ undefined reference to vtable

问题描述

我正在学习C ++。我试图做一个练习，我定义一个纯虚拟类的单个函数的几个实现。我无法链接使用这些实现的类。

  ==> BasicMath.h <== 
 #ifndef BASIC_MATH_H 
 #define BASIC_MATH_H 
 
＃include< string> 
＃include< vector> 
 
 class BasicMath {}; 
 
 
 #endif // BASIC_MATH_H 
 
 ==> Operation.h< == 
 
 #ifndef OPERATION 
 #define OPERATION 
 
＃include< string> 
＃include< vector> 
 
类操作{
 public：
 virtual void perform（std :: vector< std :: string> vec）= 0; 
}; 
 
 
 #endif //操作
 
 ==> Sum.h <== 
 #ifndef SUM_H 
 #define SUM_H 
 
 #includeOperation.h
 
类Sum：public操作{ 
 public：
 void perform（std :: vector< std :: string> vec）; 
}; 
 
 #endif // SUM_H 
 
 ==> BasicMath.cpp< == 
 #ifndef BASIC_MATH_C 
 #define BASIC_MATH_C 
 
 #include< string> 
 #include< vector> 
 #include< iostream> 
 #includeBasicMath.h
 #includeSum.h
 
 int main（int argc，char * argv []）{
 Sum op; 
} 
 
 #endif // BASIC_MATH_C 
 
 ==> Sum.cpp< == 
 #ifndef SUM_C 
 #define SUM_C 
 
 #include< vector> 
 #include< string> 
 #include< iostream> 
 #includeSum.h
 
 void Sum :: perform（std :: vector< std :: string> vec）{
 using namespace std; 
 int total = 0; 
 cout<< Total：<<总< \\\
; 
}; 
 
 #endif // SUM_C 
  

编译：

  $ g ++ -c Sum.cpp 
 $ g ++ -o BasicMath BasicMath.cpp 
 /tmp/cc1VXjNl.o:BasicMath。 cpp :(。text $ _ZN3SumC1Ev [Sum :: Sum（）] + 0x16）：未定义引用`vtable for Sum'
 collect2：ld返回1退出状态
  / pre> 
 
 <95>我95％肯定我在这里至少做一个蠢事 - 但我的大脑拒绝告诉我什么。
 
 
 
我看到这个问题，但是没有解决我的问题。
解决方案
不要在编译链接行中包含Sum.o对象文件（第二个g ++使用）。
 
I'm learning C++. I'm trying to do an exercise where I define several implementations of a pure virtual class with a single function. I'm having trouble linking the class that uses these implementations.
==> BasicMath.h <==
#ifndef BASIC_MATH_H
#define BASIC_MATH_H

#include<string>
#include<vector>    

class BasicMath { };


#endif // BASIC_MATH_H

==> Operation.h <==

#ifndef OPERATION
#define OPERATION

#include<string>
#include<vector>    

class Operation {
 public:
  virtual void perform(std::vector<std::string> vec) = 0;
};


#endif // OPERATION

==> Sum.h <==
#ifndef SUM_H
#define SUM_H

#include "Operation.h"

class Sum: public Operation {
 public:
  void perform(std::vector<std::string> vec);
};

#endif // SUM_H

==> BasicMath.cpp <==
#ifndef BASIC_MATH_C
#define BASIC_MATH_C

#include <string>
#include <vector>
#include <iostream>
#include "BasicMath.h"
#include "Sum.h"

int main(int argc, char* argv[]) {
  Sum op;
}

#endif // BASIC_MATH_C

==> Sum.cpp <==
#ifndef SUM_C
#define SUM_C

#include <vector>
#include <string>
#include <iostream>
#include "Sum.h"

void Sum::perform(std::vector<std::string> vec) {
    using namespace std;
    int total = 0;
    cout << "Total: " << total << "\n";
};

#endif // SUM_C
Compilation:
$ g++ -c Sum.cpp
$ g++ -o BasicMath BasicMath.cpp
/tmp/cc1VXjNl.o:BasicMath.cpp:(.text$_ZN3SumC1Ev[Sum::Sum()]+0x16): undefined reference to `vtable for Sum'
collect2: ld returned 1 exit status
I'm 95% sure I'm doing at least one foolish thing here - but my brain is refusing to tell me what.

I have see this question but have not managed to fix my issue.
解决方案
You're not including the Sum.o object file on your compile&link line (second g++ use).

                        
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