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有类的定义如下: class A{ private: int x,y; public: A(int m,int n){x=m;y=n;} }; Class B{ private: int z; A a; public: B(int m); }; 下列()是正确的B类构造函数实现代码。
A.B::B(int m) : a(m), z(m){ }
B.B::B(int m) : a(),z() { }
C.B::B(int m) : a(m,m), z(m){ }
D.B::B(int m) : a=(m,m), z=m { }
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)