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