C ++错误，未定义参考类 [英] C++ error, Undefined reference class

问题描述

为什么代码块会给出此错误对class :: classfunction()的未定义引用"在单独的文件中创建类时会发生这种情况.所有这些文件都在同一文件夹中

Why does codeblocks give this error "Undefined reference to class::classfunction()" It happens when a class is created in a separated file.All of these files are in the same folder

这是主要的.cpp文件

This is the main .cpp file

#include<iostream>
#include "Class2.h"

using namespace std;

main()
{
    Class2 classObject;
    cout<<"I'm class2"<<endl;

}

类头文件

#ifndef CLASS2_H
#define CLASS2_H


class Class2
{
    public:
        Class2();
        ~Class2();
    protected:
    private:
};

#endif // CLASS2_H

cpp类文件

#include "Class2.h"
#include<iostream>

using namespace std;

Class2::Class2()
{
    cout<<"Hello, I'm Constructor"<<endl;
}

Class2::~Class2()
{
    cout<<"Yo!! I'm Destructor"<<endl;
}

错误是对Class2 :: Class2()的未定义引用"

error is "undefined reference to Class2::Class2()"

推荐答案

您需要将 main.o 和 class.o 都链接到可执行文件中.确切的命令取决于您的编译器和OS.对于g ++，命令看起来像

You need to link both main.o and class.o into your executable. The exact command depends on your compiler and OS. For g++ the command would look something like

g++ -o main main.cpp class.cpp

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