CODEWITHSUNDEEP
c++
user1601045
user1601045

Reputation: 59

C++ error LNK2001 issue

I am fairly new to cpp but have been in c# for a while. I am trying to run a simple console application but I receive this LNK2001 error message.

I have the main.cpp, and have added another class, Zeus, with files, Zeus.h and Zeus.cpp.

Here is the main.cpp:

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

int main()
{
    Zeus::tick = 25.0;
    using std::cout;
    cout << "nothing";
}

Here is the Zeus.h:

static class Zeus
{
public:
    static void testing(void);
public:
    static double tick;
};

And here is the Zeus.cpp:

void Zeus::testing(void)
{
 //Doesnt get this far
 //But eventually something like
 // cout << "test " << Zeus::tick;

}

And here is the error message:

Error 20 error LNK2001: unresolved external symbol "public: static double Zeus::tick"

Thanks,

Upvotes: 0

Views: 325

Answers (3)

Kd_R
Kd_R

Reputation: 103

In the main() function you have, what do you mean by a statement Zeus::tick = 25.0;? Zeus is a class. So to access the individual elements of it you need to create its instance. Its just like a structure where you first create its instance to access its individual elements.

Try the following:

int main() {
    Zeus myobject;

    myobject.tick = 25.0;
    /* Rest of the definition */ 
}

Upvotes: 0

juanchopanza
juanchopanza

Reputation: 227548

You need to define Zeus::tick, typically you would to that in the in the Zeus.cpp file. You have only declared it.

double Zeus::tick = 0.0;

Also, there is no static class in C++.

As an aside, free functions can be put in namespaces, as opposed to being static functions of classes. This is the preferred way in C++, unless there are strong reasons for the function to be static.

namespace Dionysus {
  void testing();
}

Upvotes: 1

Pete Becker
Pete Becker

Reputation: 76458

As the error message says: there's no definition of Zeus::tick. Add this to Zeus.cpp:

double Zeus::tick;

Oh, and in Zeus.h remove the static from

static class Zeus

Upvotes: 0

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