How to hide member function file while sharing class

I am reading book How to program by Paul Deitel. As per him we can make a file which does not contain member function details.

"To hide the class’s member-function implementation details, the class-implementation programmer would provide the client-code programmer with the header Time.h (which specifies the class’s interface and data members) and the Time object code (i.e., the machine-code instructions that represent Time’s member functions). The client-code programmer is not given Time.cpp, so the client remains unaware of how Time’s member functions are implemented."

I have developed below simple code in dev to test this concept but I don't know after compiling which file is the equivalent to cpp file.

Area Class:

#include<iostream>
using namespace std;
class Area {

    public:
        int square(int);

    private:
        int x;  
};

Source Code Area.cpp which contains member function functionality

#include<iostream>
#ifndef AREA_HH
#define AREA_HH
# include "Area.h"

int Area::square(int x)
{
    return x*x;
}

#endif

Main:

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

using namespace std;

int main ()

{
    Area Obj1;

    cout<<Obj1.square(4);

    return 0;
}

The Files created by Dev are: Area.cpp, Area.o,Area.h,main.cpp,main.o,Makefile.win,layout and exe.