Exercises6
1、写出广义表表示法表示的树的类声明，并给出如下成员函数的实现：
（1） operator>>( ) 接收用广义表表示法表示的树作为输入，建立广义表的存储表示；
（2） 复制构造函数 用另一棵表示为广义表的树初始化一棵树；
（3） operator= = ( ) 测试用广义表表示的两棵树是否相等；
（4） operator<<( ) 用广义表的形式输出一棵树；
（5） 析构函数 清除一棵用广义表表示的树。
2、Start with PointerToMemberOperator.cpp and show that polymorphism still works with pointers-to-members,even if operator->* is overloaded.
//PointerToMemberOperator.cpp
#include <iostream>
using namespace std;
class Dog {
public:
int run(int i) const {
cout << "run\n";
return i;
}
int eat(int i) const {
cout << "eat\n";
return i;
}
int sleep(int i) const {
cout << "ZZZ\n";
return i;
}
typedef int (Dog::*PMF)(int) const;
// operator->* must return an object
// that has an operator():
class FunctionObject {
Dog* ptr;
PMF pmem;
public:
// Save the object pointer and member pointer
FunctionObject(Dog* wp,PMF pmf)
,ptr(wp),pmem(pmf) {
cout << "FunctionObject constructor\n";
}
// Make the call using the object pointer
// and member pointer
int operator()(int i) const {
cout << "FunctionObject::operator()\n";
return (ptr->*pmem)(i); // Make the call
}
};
FunctionObject operator->*(PMF pmf) {
cout << "operator->*" << endl;
return FunctionObject(this,pmf);
}
};
int main() {
Dog w;
Dog::PMF pmf = &Dog::run;
cout << (w->*pmf)(1) << endl;
pmf = &Dog::sleep;
cout << (w->*pmf)(2) << endl;
pmf = &Dog::eat;
cout << (w->*pmf)(3) << endl;
} ///:~