can anyone help me on this inheritance problem

hello guys...i just done my assignment and here's the code

Code:

#include <iostream>

using namespace std;

class CelestialBody
{

private:
double size;
public:
    CelestialBody (double );
;

class Planet : public CelestialBody
{
private:

double orbit_time;
public:
  Planet(double , double);

};

Class Earth : public Planet

{

private:
unsigned long int population ;

public:

   Earth();
};

Celestialbody :: Celestialbody (double) :
size(SIZE)
{
cout<<"CelestialBody is called"<<endl;
}

Planet :: Planet (double) : size(SIZE) , orbit_time(ORBIT_TIME)
{
cout <<  "Planet constructor is called"<<endl;





Earth :: Earth ()

: Planet (1,40000), population (3000000000)

{

cout <<" Earth constructor is called."<<endl;
cout <<"Population =" <<population <<endl;
cout<<"orbit time = "<<orbit_time<< endl;
cout<< "size =" <<size <<endl;



int main ()


{
Earth earth;

return 0;

}

the output should be like this

Code:

 
CelestialBody constructor is called
Planet constructor is called
Population  constructor is called

Population = 5000000000

orbit time = 1

size = 40000

all looks fine but
but i am stuck in the earth class and constructor section.
I think i was mistaken in the area of calling of the CelestialBody constructor to initialize the
data members of both the Planet and CelestialBody.
I didn't declared SIZE and ORBIT_TIME but it will not effect the end results will it?
any help plez..i did my homework..need for it to be compiled..

Aside from lacking a closing curly brace, which is an error present elsewhere in the code too, the Earth constructor looks ok.

What exactly are you unsure about?