[repost} C++ Code Block

Question

Can someone help me what am I doing wrong here?
----------------------------------------------------------------------------------------------------
main cpp
-------------------
#include <iostream>
#include "MeineClassfirst.h"

using namespace std;

int main(){
MeineClassfirst obj;
obj.myPrint();
cout << "Hello world!" << endl;
return 0;
}
--------------------------------
MeineClassfirst.h
-------------------------------
#ifndef MEINECLASSFIRST_H
#define MEINECLASSFIRST_H
#include <iostream>

class MeineClassfirst
{
public:
MeineClassfirst();
void myPrint();
~MeineClassfirst();

protected:

private:

};

#endif // MEINECLASSFIRST_H

-------------------------------------
MeineClassfirst.cpp
------------------------------------
#include "MeineClassfirst.h"
#include <iostream>
using namespace std;

MeineClassfirst::MeineClassfirst()
{
cout<<"Constructor"<<endl;
//ctor
}
void MeineClassfirst::myPrint(){
cout<<"Hello"<<endl;
}
MeineClassfirst::~MeineClassfirst()
{
cout<<"Destructor"<<endl;
}
--------------------------------------------------
After the run build messages shows
-----------------------------
// Line// 7 undefined reference to 'MeineClassfirst::MeineClassfirst()'
//Line// 8 undefined reference to 'MeinClassfirst::myPrint()'
//Line// 7 undefined reference to 'MeineClassfirst::~MeineClassfirst()'
//Line// 7 undefined reference to 'MeineClassfirst::~MeineClassfirst()'
---------------------------------------
Thank you!

Answer 1

Bbrbk Your error stems from the fact that the linker cannot find the 4 functions you've listed above.
You can resolve this issue in two ways:

1.Ensure that you compile and run your code in code blocks as a project.That way,the IDE will pass the necessary .o(object) files to the linker.

2.add
#include "MeineClassfirst.cpp"
To your main.cpp file.(Though I don't recommend using this method since it kind of beats the purpose of separating the interface from the implementation.)

Answer 2

What's your error?

Answer 3

After the run build messages shows
-----------------------------
// Line// 7 undefined reference to 'MeineClassfirst::MeineClassfirst()'
//Line// 8 undefined reference to 'MeinClassfirst::myPrint()'
//Line// 7 undefined reference to 'MeineClassfirst::~MeineClassfirst()'
//Line// 7 undefined reference to 'MeineClassfirst::~MeineClassfirst()'
---------------------------------------
Thank you!