Question about design class..
Hi, I have a question about how to design a class.
I am really confused about how objects interact with others.
I know most of the syntax of c++, polymorphism, inhertiance, template as well.
But like others said, knowing syntax do not automatically make u a good programmer.
For eg, if after analysis, I choose to define 10 user define type class A, class B, class C, ..., Class J.
Is it normal if I instance all this objects globally?
That means all if method of A wants to communicate B, it can just directly use global instance b1. Is this acceptable in OOP design?
If I use composition, for example:
Code:
class B {
public:
void operate() {dosomething;}
private:
_data of B;
}
class A {
public:
void method1() {_pb->operate();}
private:
B* _pb;
};
Sometimes I confront of situation tat operate() method of B needs to know some data of A in order to operate.
But it can't not.
Then a solution I first think of is to add friendship of class A to B;
Seems a really bad idea.
Then I will try to drag B* _pb out of class A
And instance A a1, B b1, globally.
Code:
void A::method1() {
b1.operate(); // Call global b1 instance
}
void A::method1() {
a1.methodxxx() // may need to call a1,too
}
If I confront this. How should I resolve this condition?
If the compsition relation is much larger;
like
Code:
class D {
public:
void methodD() { need to know some information about class A ??} // what should I do?
}
class C {
public:
void methodC() { _pd->methodD();}
private:
D* _pd;
}
class B {
public:
void methodB() {_pc->methodC();}
private:
C* _pc;
}
class A {
public:
void methodA() {_pb->methodB();}
private:
B* _pb;
};
Does that mean I need to redesign my class?
