作业1：
1.定义一个矩形类Rec，包含私有属性length、width，包含公有成员方法：
void set_length(int l);//设置长度
Void set_width(int w);//设置宽度
Int get_length();//获取长度，将长度的值返回给调用处
Int get_width();//获取宽度，将宽度的值返回给调用处
Void show();//输出周长和面积
#include <iostream>using namespace std;
class Rec{const int length;int width;
public:Rec():length(5),width(6){cout<<"无参构造:length="<<length<<"width="<<width<<endl;}Rec(int len,int wid):length(len){width=wid;cout<<"有参构造1:length="<<length<<"width="<<width<<endl;}Rec(int len):length(len){cout<<"有参构造2:length="<<length<<"width="<<width<<endl;}//void set_length(int l);void set_width(int w);int get_length();int get_width();void show();
};void Rec::set_width(int w)
{width=w;
}
int Rec::get_length()
{return length;
}
int Rec::get_width()
{return width;
}
void Rec::show()
{cout<<"周长："<<length*2+width*2<<endl;cout<<"面积："<<length*width<<endl;
}
int main()
{Rec rec;cout<<"length="<<rec.get_length()<<endl;cout<<"width="<<rec.get_width()<<endl;rec.show();cout << "****************" << endl;Rec rec1(4,1);cout<<"length="<<rec1.get_length()<<endl;cout<<"width="<<rec1.get_width()<<endl;rec1.show();cout << "****************" << endl;Rec rec2(3);cout<<"length="<<rec2.get_length()<<endl;cout<<"width="<<rec2.get_width()<<endl;rec2.show();return 0;
}
作业2：
2.定义一个圆类，包含私有属性半径r，公有成员方法：
Void set_r(int r);//获取半径
Void show();//输出周长和面积，show函数中需要一个提供圆周率的参数PI，该参数默认值3.14
#include <iostream>using namespace std;
class Yuan{int &r;
public:Yuan(int &r1):r(r1){cout<<"有参构造r="<<r<<endl;}void set_r(int &r);void show(double PI=3.14);
};
void Yuan::set_r(int &r)
{this->r=r;
}
void Yuan::show(double PI)
{double l=2*PI*r;double a=PI*r*r;cout<<"周长："<<l<<endl;cout<<"面积："<<a<<endl;
}
int main()
{int r=1;Yuan yuan(r);yuan.show();int r1=2;yuan.set_r(r1);yuan.show();cout << "Hello World!" << endl;return 0;
}作业3：
定义一个Car类，包含私有属性，颜色color，品牌brand，速度speed，包含公有成员方法：
Void display();//显示汽车的品牌，颜色和速度
Void acc(int a);//加速汽车
set函数，设置类中的私有属性
#include <iostream>using namespace std;
class Car{string color;string brand;int speed;
public:Car(){cout<<"无参构造"<<endl;}Car(string color,string brand,int speed){this->color=color;this->brand=brand;this->speed=speed;cout<<"有参构造"<<endl;}void set(string,string,int);void display();void acc(int a);
};
void Car::set(string color,string brand,int speed)
{this->color=color;this->brand=brand;this->speed=speed;
}
void Car::display()
{cout<<"color:"<<color<<endl;cout<<"brand:"<<brand<<endl;cout<<"speed:"<<speed<<endl;
}
void Car::acc(int a)
{speed+=a;
}int main()
{Car car;car.set("红色","车",100);car.display();car.acc(1);car.display();Car car1("白色","奥迪",200);car1.display();car1.acc(2);car1.display();cout << "Hello World!" << endl;return 0;
}