拷贝控制示例
- #include<iostream>
- #include<string>
- #include<set>
- using namespace std;
- class Folder;
- class Message {
- friend void swap(Message&, Message&);
- friend class Folder;
- public:
- explicit Message(const string &str = ""): contents(str) {}
- Message(const Message&);
- Message& operator=(const Message&);
- ~Message();
- Message(Message&&);
- Message& operator=(Message&&);
- void save(Folder&);
- void remove(Folder&);
- void debug_print();
- private:
- string contents;
- set<Folder*> folders;
- void add_to_Folders(const Message&);
- void move_Folders(Message*);
- void remove_from_Folders();
- void addFldr(Folder *f) { folders.insert(f); }
- void remFldr(Folder *f) { folders.erase(f); }
- };
- class Folder {
- friend void swap(Message&, Message&);
- friend class Message;
- public:
- Folder() = default;
- Folder(const Folder&);
- Folder& operator=(const Folder&);
- Folder(Folder&&);
- Folder& operator=(Folder&&);
- ~Folder();
- void save(Message&);
- void remove(Message&);
- void debug_print();
- private:
- set<Message*> msgs;
- void add_to_Messages(const Folder&);
- void remove_from_Msgs();
- void addMsg(Message *m) { msgs.insert(m); }
- void remMsg(Message *m) { msgs.erase(m); }
- void move_Messages(Folder*);
- };
- /*********************************************************************/
- Message::Message(const Message &m) : contents(m.contents), folders(m.folders)
- {
- add_to_Folders(m);
- }
- void Message::add_to_Folders(const Message &m)
- {
- for (auto f : m.folders)
- f->addMsg(this);
- }
- Message& Message::operator=(const Message &rhs)
- {
- remove_from_Folders();
- contents = rhs.contents;
- folders = rhs.folders;
- add_to_Folders(rhs);
- return *this;
- }
- void Message::remove_from_Folders()
- {
- for (auto f : folders)
- f->remMsg(this);
- folders.clear();
- }
- Message::Message(Message &&m) : contents(std::move(m.contents))
- {
- move_Folders(&m);
- }
- Message& Message::operator=(Message &&rhs)
- {
- if (this != &rhs)
- {
- remove_from_Folders();
- contents = std::move(rhs.contents);
- }
- return *this;
- }
- Message::~Message()
- {
- remove_from_Folders();
- }
- void Message::save(Folder &f)
- {
- folders.insert(&f);
- f.addMsg(this);
- }
- void Message::remove(Folder &f)
- {
- folders.erase(&f);
- f.remMsg(this);
- }
- void Message::debug_print()
- {
- cerr <<"Message:\n\t" << contents << endl;
- cerr << "Appears in" << folders.size() << "Folders" << endl;
- }
- Folder::Folder(Folder &&f)
- {
- move_Messages(&f);
- }
- void Message::move_Folders(Message *m)
- {
- folders = std::move(m->folders);
- for (auto f : folders)
- {
- f->remMsg(m);
- f->addMsg(this);
- }
- m->folders.clear();
- }
- void swap(Message &lhs, Message &rhs)
- {
- using std::swap;
- for (auto f : lhs.folders)
- f->remMsg(&lhs);
- for (auto f : rhs.folders)
- f->remMsg(&rhs);
- swap(lhs.folders, rhs.folders);
- swap(lhs.contents, rhs.contents);
- for (auto f : lhs.folders)
- f->addMsg(&lhs);
- for (auto f : rhs.folders)
- f->addMsg(&rhs);
- }
- /*********************************************************************/
- Folder::Folder(Folder &&f)
- {
- move_Messages(&f);
- }
- Folder& Folder::operator=(Folder &&f)
- {
- if (this != &f) {
- remove_from_Msgs();
- move_Messages(&f);
- }
- return *this;
- }
- Folder::Folder(const Folder &f) : msgs(f.msgs)
- {
- add_to_Messages(f);
- }
- void Folder::add_to_Messages(const Folder &f)
- {
- for (auto msg : f.msgs)
- msg->addFldr(this);
- }
- Folder& Folder::operator=(const Folder &f)
- {
- remove_from_Msgs();
- msgs = f.msgs;
- add_to_Messages(f);
- return *this;
- }
- void Folder::remove_from_Msgs()
- {
- while (!msgs.empty())
- (*msgs.begin())->remove(*this);
- }
- Folder::~Folder()
- {
- remove_from_Msgs();
- }
- void Folder::save(Message &m)
- {
- msgs.insert(&m);
- m.addFldr(this);
- }
- void Folder::remove(Message &m)
- {
- msgs.erase(&m);
- m.remFldr(this);
- }
- void Folder::debug_print()
- {
- cerr <<"Folder contains" << msgs.size() << "messages" << endl;
- int ctr = 1;
- for (auto m : msgs)
- {
- cerr << "Message" << ctr++ << ":\n\t" << m->contents <<endl;
- }
- }
- int main()
- {
- string s1("contents1");
- string s2("contents2");
- string s3("contents3");
- string s4("contents4");
- string s5("contents5");
- string s6("contents6");
- Message m1(s1);
- Message m2(s2);
- Message m3(s3);
- Message m4(s4);
- Message m5(s5);
- Message m6(s6);
- Folder f1;
- Folder f2;
- m1.save(f1); m3.save(f1); m5.save(f1);
- m1.save(f2);
- m2.save(f2); m4.save(f2); m6.save(f2);
- m1.debug_print();
- f2.debug_print();
- Message c1(m1);
- Message c2(m2), c4(m4), c6(m6);
- m1.debug_print();
- f2.debug_print();
- m2 = m3;
- m4 = m5;
- m6 = m3;
- m1 = m5;
- m1.debug_print();
- f2.debug_print();
- m2 = m2;
- m1 = m1;
- m1.debug_print();
- f2.debug_print();
- vector<Message> vm;
- cout <<"capacity:" << vm.capacity() << endl;
- vm.push_back(m1);
- cout << "capacity:" << vm.capacity() << endl;
- vm.push_back(m2);
- cout << "capacity:" << vm.capacity() << endl;
- vm.push_back(m3);
- cout << "capacity:" << vm.capacity() << endl;
- vm.push_back(m4);
- cout << "capacity:" << vm.capacity() << endl;
- vm.push_back(m5);
- cout << "capacity:" << vm.capacity() << endl;
- vm.push_back(m6);
- vector<Folder> vf;
- cout << "capacity:" << vf.capacity() << endl;
- vf.push_back(f1);
- cout << "capacity:" << vf.capacity() << endl;
- vf.push_back(f2);
- cout << "capacity:" << vf.capacity() << endl;
- vf.push_back(Folder(f1));
- cout << "capacity:" << vf.capacity() << endl;
- vf.push_back(Folder(f2));
- cout << "capacity:" << vf.capacity() << endl;
- vf.push_back(Folder());
- Folder f3;
- f3.save(m6);
- cout << "capacity:" << vf.capacity() << endl;
- vf.push_back(f3);
- return 0;
- }
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