How does C handle copy constructors for classes containing other objects?

Implicit Copy Constructor for Classes Containing Other Objects in C

In C , when a class does not explicitly declare a copy constructor, the compiler may generate an implicit copy constructor to facilitate object initialization and copying. However, the behavior of this implicit constructor can be confusing, especially when the class contains other objects.

Consider the following class structure:

class Foo {
  Bar bar;
};

class Bar {
  int i;
  Baz baz;
};

class Baz {
  int j;
};

If we create an instance of Foo and attempt to initialize another instance by copying the first one:

Foo f1;
Foo f2(f1);

The compiler will generate the following implicit copy constructors:

Foo::Foo(Foo const& copy)
    : bar(copy.bar) {}

Bar::Bar(Bar const& copy)
    : i(copy.i), baz(copy.baz) {}

Baz::Baz(Baz const& copy)
    : j(copy.j) {}

These constructors will perform shallow copies of the respective objects, recursively copying all member variables. Therefore, the default copy constructor in Foo will indeed call the default copy constructor in Bar, which will in turn call the default copy constructor in Baz.

It's important to note that this implicit copy constructor only performs shallow copies. If the member objects contain pointers or other complex data structures, their copies must be explicitly handled to ensure proper initialization and resource management.

The above is the detailed content of How does C handle copy constructors for classes containing other objects?. For more information, please follow other related articles on the PHP Chinese website!