C++ Programming - 7th Study
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This document discusses the rule of three/five in C++ and provides examples of deep copying for a Person class. It shows how to properly implement a copy constructor, copy assignment operator, and destructor to manage memory on the heap. Without following the rule of three/five, issues like shallow copying, dangling pointers, and memory leaks can occur when objects are copied or assigned.
![class Person {
private:
int* room;
int roomNum;
double height;
double weight;
public:
Person() { }
Person(int _roomNum, double _height, double _weight)
: roomNum(_roomNum), height(_height), weight(_weight) {
room = new int[roomNum];
}
~Person() {
delete[] room;
}
};
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![Person(const Person& src)
: roomNum(src.roomNum), height(src.height), weight(src.weight)
{
room = new int[roomNum];
for (int i = 0; i < roomNum; ++i)
room[i] = src.room[i];
}
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![Person& operator=(const Person& rhs) {
if (this == &rhs)
return *this;
delete[] room;
room = nullptr;
height = rhs.height;
weight = rhs.weight;
roomNum = rhs.roomNum;
room = new int[roomNum];
for (int i = 0; i < roomNum; ++i)
room[i] = rhs.room[i];
return *this;
}
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C++ Programming - 7th Study
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- 5. // 1 Person(const Person& src) : height(src.height), weight(src.weight) { } // 2 Person(const Person& src) { height = src.height; weight = src.height; } int main() { Person p1(183.4, 78.5); Person p2(p1); } 5
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- 12. Person& operator=(const Person& rhs) { if (this == &rhs) return *this; height = rhs.height; weight = rhs.weight; return *this; } int main() { Person p1(183.4, 78.5), p2(175.6, 68.3); p1 = p2; } 12
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- 16. Person p1 Person p2 int roomNum 3 183.4 double height 78.5 double weight int* room int roomNum 5 175.6 double height 68.3 double weight int* room 스택(Stack) 메모리 힙(Heap) 메모리 16
- 17. Person p1 Person p2 int roomNum 3 183.4 double height 78.5 double weight int* room int roomNum 5 175.6 double height 68.3 double weight int* room 스택(Stack) 메모리 힙(Heap) 메모리 주인이 없어진 메모리! (Orphaned Memory) 17
- 18. Person p1 Person p int roomNum 3 183.4 double height 78.5 double weight int* room int roomNum 3 183.4 double height 78.5 double weight int* room 스택(Stack) 메모리 힙(Heap) 메모리 printRoom는 방의 정보를 출력하는 함수 함수가 호출되면서 얕은 복사로 인해 포인터만 복사되고 데이터는 복사되지 않음 18
- 19. Person p1 int roomNum 3 183.4 double height 78.5 double weight int* room 스택(Stack) 메모리 힙(Heap) 메모리 반환 해제된 메모리 → 댕글링 포인터(Dangling Pointer) printRoom 함수가 리턴하면 스택 객체인 p의 소멸자가 호출되면서 room 포인터가 가리키는 메모리를 해제함 19
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- 21. class Person { private: int* room; int roomNum; double height; double weight; public: Person() { } Person(int _roomNum, double _height, double _weight) : roomNum(_roomNum), height(_height), weight(_weight) { room = new int[roomNum]; } ~Person() { delete[] room; } }; 21
- 22. int main() { Person p1(3, 183.4, 78.5); Person p2(5, 175.6, 68.3); p1 = p2; } 22
- 23. void printRoom(Person p) { } int main() { Person p1(3, 183.4, 78.5); printRoom(p1); } 23
- 24. Person(const Person& src) : roomNum(src.roomNum), height(src.height), weight(src.weight) { room = new int[roomNum]; for (int i = 0; i < roomNum; ++i) room[i] = src.room[i]; } 24
- 25. Person& operator=(const Person& rhs) { if (this == &rhs) return *this; delete[] room; room = nullptr; height = rhs.height; weight = rhs.weight; roomNum = rhs.roomNum; room = new int[roomNum]; for (int i = 0; i < roomNum; ++i) room[i] = rhs.room[i]; return *this; } 25