[C++知识库]C++设计并实现加法器类Adder

#include <iostream>
using namespace std;
class Adder
{
private:
    int num;
public:
    Adder(int n=0);//有参构造函数，其中参数默认值为0
    Adder(const Adder &adder);//拷贝构造函数
    ~Adder();//析构函数
    void  setNum(int n);//公有函数，用于设置数值域
    int getNum() const;//公有函数，用于返回数值域
    Adder operator+(Adder &a);//重载+运算符
    Adder& operator++(void);//前置++运算符重载
    const Adder operator++(int);//后置++运算符重载
    void show() const;//显示
};
Adder::Adder(int n)//有参构造函数的实现
{
    num=n;
    cout<<"Adder Constructor run"<<endl;
}
Adder::Adder(const Adder &adder)//拷贝构造函数的实现
{
    num = adder.num;
    cout<<"Adder CopyConstructor run"<<endl;
}
Adder::~Adder()//析构函数的实现
{
    cout<<"Adder Destructor run"<<endl;
}
void Adder::setNum(int n)
{
    num=n;
}
int Adder::getNum()const
{
    return num;
}
Adder Adder::operator+(Adder &a)//重载+运算符
{
    this->num = this->num + a.num;
    return (Adder(getNum()));
}
Adder& Adder::operator++(void)//前置重载++运算符
{
    num++;
    return *this;
}
const Adder Adder::operator++(int)//后置重载++运算符
{
    Adder ad=*this;
    ++(*this);
    return ad;
}
void Adder::show()const
{
    cout<<"Adder("<<num<<")"<<endl;
}
//主函数
int main(void){
    int x;
    Adder a1,a2(a1);
    cin>>x;
    (a1++).show();
    a1.show();
    a2.setNum(x);
    (++a2).show();
    a2.show();
    (a1+a2).show();
    return 0;
}