有如下程序： #include＜iostream＞ using namespace std; class Part public: Part(int x=0):val(x) cout＜＜val; ～Part()cout＜＜val; private: int val; ; class Whole public: Whole(int x ,int y, int z=0):p2(x),p1(y),val(z)cout＜＜val; ～Whole()cout＜＜val; private: Part p1,p2; int val; ; int main() Whole obj(1,2,3); return 0;