考虑:
class A
{
public:
A( int val ) : m_ValA( val ) {}
A( const A& rhs ) {}
int m_ValA;
};
class B : public A
{
public:
B( int val4A, int val4B ) : A( val4A ), m_ValB( val4B ) {}
B( const B& rhs ) : A( rhs ), m_ValB( rhs.m_ValB ) {}
int m_ValB;
};
int main()
{
A* b1 = new B( 1, 2 );
A* b2 = new A( *b1 ); // ERROR...but what if it could work?
return 0;
}
如果“new A( b1)”能够解决创建新的 B 副本并返回 A , C++ 会被破坏吗?
这甚至会有用吗?