编译-链接.cpp&时出错头文件 [英] error when compiling - linking .cpp & header file

问题描述

我正在尝试将.cpp实现文件与头文件链接-我从mac终端收到此错误消息-

I'm attempting to link my .cpp implementation file with my header file - I get this error message from my mac terminal -

rowlandev:playground rowlandev$ g++ main.cpp -o main
Undefined symbols for architecture x86_64:
  "Person::Person()", referenced from:
      _main in main-32e73b.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

这是我的cpp文件中的代码:

Here is the code in my cpp file:

#include <iostream>
#include "playground.h"

using namespace std;

Person::Person() {
    cout << "this is running from the implementation file" << endl;
}

这是我主要功能的代码:

here is the code with my main function:

#include <iostream>
#include "playground.h"

using namespace std;

int main() {
    Person chase;
}

这是我的头文件中的代码:

and here is the code in my header file:

  #include <string>

    using namespace std;


    #ifndef playground_h
    #define playground_h

    class Person {
    public:
        Person();
    private:
        string name;
        int age;
    };


    #endif /* playground_h */

我该怎么做才能解决此错误?随意添加我可以做的其他任何事情来改进我刚刚编写的代码.向任何事物敞开.

what should I do to fix this error? Feel free to add any other things I can do to improve the code I just wrote. Open to anything.

推荐答案

如果您尝试从源代码创建可执行文件，请阅读以下内容:

Here's a good read to understand what's going on when you try to create an executable from source code: How does the compilation/linking process work?

这里发生的是链接器不知道在main()中被调用的Person::Person()的位置.请注意，当您调用g ++时，从未将文件提供给您为Person::Person()编写代码的地方.

What's going on here is that the linker doesn't know where Person::Person(), which is being called in main(), is located. Notice how when you called g++, you never gave it the file where you wrote code for Person::Person().

调用g ++的正确方法是: $ g++ -o main main.cpp person.cpp

The right way to call g++ is: $ g++ -o main main.cpp person.cpp

这篇关于编译-链接.cpp&时出错头文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！