How to define a virtual class member function in .cpp file that is declared in .h file

[kapil2905]

Hi, I am trying to put all class declarations in .h file and all definitions in .cpp files.
But I am unable to define virtual class member functions in this way and getting error :

String.cpp:33:1: error: ‘virtual’ outside class declaration
 virtual String::~String()

String.h

#include <cstring>

class String
{
    private:
        size_t size;
        char *charString;

    public:
        String();
        virtual ~String();
};

String.cpp

String::String() : size(0), charString(NULL) {}

virtual String::~String()
{
    delete charString;
}

[Golden Lizard]

You need the virtual keyword only inside the class declaration.

#include <iostream>

class object
{
  public:

      virtual void x();   
};

void object::x()
{
    std::wcout<<L"Object called\n";
}

class derived: public object
{
    public:

        void x();
};

void derived::x()
{
    std::wcout<<L"Derived called\n";
}


int main()
{
  object * obj=new derived();
  obj->x();
  return EXIT_SUCCESS;
}

Output:

Derived called

Also, inside the destructor you may want to use the following:

String::~String()
{
    delete[] charString;
}

[kapil2905]

Thanks @Golden Lizard :)