Thread: size of Object c++ compile problem

Your compiler usually tells you why it won't compile. They're called "error messages". In this case, I get:

Code:

main.cpp(36) : error C2065: 'X' : undeclared identifier
main.cpp(36) : error C2065: 'px' : undeclared identifier
main.cpp(36) : error C2061: syntax error : identifier 'X'
main.cpp(39) : error C2516: 'X' : is not a legal base class

You'll have to rearrange your class definitions a bit.

Code:

class X {
public:
virtual void f1() = 0;
virtual ~X(){}
int a;
static int sa;
};

class Y : public X  {
public:
void f1() {}
virtual void f2(){}
int b;
};

int main()
{
X *px = new X;
}

Even then it won't work because X is an abstract class. It has a pure virtual function, f1(). You can have a pointer to X, but you cannot make a new X.

You also need to put in something to take care of that static data member:

Code:

int X::sa;

Finding out the size should be a simple matter of using the sizeof operator:

Code:

cout << "Size of X is: " << sizeof(X) << endl;
cout << "Size of Y is: " << sizeof(Y) << endl;