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1.1_类之间嵌套.cpp
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1.1_类之间嵌套.cpp
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//
// Created by light on 19-12-9.
//
#include <iostream>
class Animal {
public:
Animal() {
std::cout << "Animal() is called" << std::endl;
}
Animal(const Animal &) {
std::cout << "Animal (const Animal &) is called" << std::endl;
}
Animal &operator=(const Animal &) {
std::cout << "Animal & operator=(const Animal &) is called" << std::endl;
return *this;
}
~Animal() {
std::cout << "~Animal() is called" << std::endl;
}
};
class Dog {
public:
// 第一种: 使用初始化列表。
Dog(const Animal &animal) : __animal(animal) {
std::cout << "Dog(const Animal &animal) is called" << std::endl;
}
// 第二种:构造函数赋值来初始化对象。
// Dog(const Animal &animal) {
// __animal = animal;
// std::cout << "Dog(const Animal &animal) is called" << std::endl;
// }
~Dog() {
std::cout << "~Dog() is called" << std::endl;
}
private:
Animal __animal;
};
int main() {
Animal animal;
std::cout << std::endl;
Dog d(animal);
std::cout << std::endl;
return 0;
}