一、基类默认构造函数
#include<iostream>
using std::cout;
using std::endl;
//任务:基类默认构造函数的使用
//B:public ;
class A
{
//base class
public:
A() = default;
A(int i) {
cout << "A(" << i << ")" << endl; }
};
class B :public A
{
public:
B() {
cout << "B()" << endl; }
B(int j) :A(j) {
cout << "B(" << j << ")" << endl; }
};
int main()
{
A a1();
A a2{
1 };
B b1{
};
B b2{
2 };
std::cin.get();
}
结果如上图所示。
二、构造与析构
//任务1:创建类结构:Computer->PC->Desktop/Laptop以及相应的ctor/dtor
//main中创建Desktop/laptop的对象,观察ctor/dtor调用次序
//任务2:增加类Camera作为Laptop的内嵌对象c的类型
//main中创建Laptop对象,观察内嵌对象c的构造与基类构造次序
#include<iostream>
using std::cout;
using std::endl;
class Computer
{
public:
Computer() {
cout << "Computer" << endl; }
~Computer() {
cout << "~Computer" << endl; }
};
class PC :public Computer
{
public:
PC() {
cout << "PC()" << endl; }
~PC() {
cout << "~pc()" << endl; }
};
class Desktop :public PC
{
public:
Desktop() {
cout << "Desktop()" << endl; }
~Desktop(){
cout << "~Desktop" << endl; }
};
class Camera
{
public:
Camera() {
cout << "Embeddded Camera()" << endl; }
~Camera() {
cout << "Embeddded ~Camera()" << endl; }
};
class Laptop :public PC
{
private:
Camera c{
};
public:
Laptop() {
cout << "Laptop()" << endl; }
~Laptop() {
cout << "~Laptop()" << endl; }
};
int main()
{
{
Desktop d{
};
Laptop l{
};
}
}
结果如上图所示。