cpp
#include <iostream>
using namespace std;
class Rec
{
int lenth;
int width;
public:
void set_lenth(int l);
void set_width(int w);
int get_lenth();
int get_width();
void show();
};
void Rec::set_lenth(int l)
{
lenth=l;
}
void Rec::set_width(int w)
{
width=w;
}
int Rec::get_lenth()
{
return lenth;
}
int Rec::get_width()
{
return width;
}
void Rec::show()
{
int c=lenth*2+width*2;
int s=lenth*width;
cout << "周长=" << c << " 面积=" << s <<endl;
}
int main()
{
Rec p;
p.set_lenth(8);
p.set_width(9);
cout<< "Rec_lenth=" <<p.get_lenth()<<endl;
cout<< "Rec_width=" <<p.get_width()<<endl;
p.show();
return 0;
}

cpp
#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
class Circle
{
int r;
public:
void set_r(int m);
void show(double PI=3.14);
};
void Circle::set_r(int m)
{
r=m;
}
void Circle::show(double PI)
{
float c=2*PI*r;
cout << setprecision(4) << "圆的周长="<<c<<endl;
float s=PI*pow(r,2);
cout << setprecision(4) << "圆的面积="<<s<<endl;
}
int main()
{
Circle p;
p.set_r(5);
p.show();
return 0;
}

cpp
#include <iostream>
using namespace std;
class Car
{
string brand;
string color;
int speed;
public:
void set(string b,string c,int s);
void display();
void accelerate(int amount);
};
void Car::set(string b,string c,int s)
{
brand=b;
color=c;
speed=s;
}
void Car::display()
{
cout << "brand:" << brand << " color:" << color << " speed:" << speed <<endl;
}
void Car:: accelerate(int amount)
{
cout << "加速前speed=" << speed;
speed+=amount;
cout << " 加速后speed=" << speed << endl;
}
int main()
{
Car mi;
mi.set("xiaomi","blue",200);
mi.display();
mi.accelerate(100);
return 0;
}

