C++ undefined reference to WinMain@16 (Code::Blocks)

I’m learning C++ with Code::Blocks, and everytime i try to create a new class, I get an error message saying:

undefined reference to `WinMain@16'

Here’s the code I’ve been using:

Main Class

#include "Lime.h"
#include <iostream>
using namespace std;
int main()
{
    Lime lime;
    return 0;
}

Lime Class (.ccp):

#include "Lime.h"
#include <iostream>
using namespace std;
Lime::Lime()
{
    cout<<"Hi!";
}

Lime Header (.h):

#ifndef LIME_H
#define LIME_H
class Lime
{
    public:
        Lime();
};
#endif

If someone knows, how to fix it, please, tell me!