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LSP里氏替换原则----正方形不是长方形和鸵鸟不是鸟的测试程序，
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@H_
301_0@//面向对象设计原则：LSP里氏替换原则
//正方形不是长方形的测试程序
#include <iostream>
using namespace std;
//长方形类Rectangle
class Rectangle
{
private:
int width;
int height;
public:
int getWidth(){ return width; }
virtual void setWidth(int w){ width=w; }
int getHeight(){ return height; }
virtual void setHeight(int h){ height=h; }
};
//正方形类Square
class Square :public Rectangle
{public:
void setWidth(int w)
{Rectangle::setHeight(w);
Rectangle::setWidth(w);
}
void setHeight(int h)
{Rectangle::setHeight(h);
Rectangle::setWidth(h);
}
};
//测试类 TestRectangle
class TestRectangle
{ public:
void resize(Rectangle &objRect)
{while(objRect.getWidth() <= objRect.getHeight() )
{objRect.setWidth( objRect.getWidth() + 1 );}
cout<<"resize over!"<<endl;
cout<<"height="<<objRect.getHeight()<<" width="<<objRect.getWidth()<<endl;;
}
};
//主
函数
int main()
{
Rectangle r; //
父类对象
r.setWidth(5);
r.setHeight(15);
Square s; //子类对象
s.setWidth(5);
s.setHeight(15);
TestRectangle t;
t.resize(r); //ok
t.resize(s); //用子类对象代替
父类对象时，出现无限循环
return 0;
}
（2）
@H_
301_0@//面向对象设计原则：LSP里氏替换原则
//鸵鸟不是鸟的测试程序
#include <iostream>
using namespace std;
//鸟类Bird
class Bird
{
private:
double velocity;
public:
virtual void fly() { cout<<"I can fly!"; }
virtual void setVelocity(double v) { velocity = v; }
virtual double getVelocity() { return velocity; }
};
//鸵鸟类Ostrich
class Ostrich :public Bird
{ public:
void fly() { cout<<"i can\'t fly!"; }
void setVelocity(double v) { Bird::setVelocity(0); }
double getVelocity() { return Bird::getVelocity(); }
};
//测试类TestBird:
class TestBird
{public:
void calcFlyTime(Bird &bird)
{try
{double riverWidth = 3000;
if(bird.getVelocity()==0) throw 0;
cout<<"Velocity="<<bird.getVelocity()<<endl;
cout<<"Fly time="<<riverWidth/bird.getVelocity()<<endl;
} catch(int)
{ cout<<"An error occured!"<<endl; }
}
};
//主
函数
int main()
{
Bird b; //
父类对象
b.setVelocity(100);
Ostrich o;
o.setVelocity(0);
TestBird t;
t.calcFlyTime(b); //ok
t.calcFlyTime(o); //用子类对象代替
父类对象时，出现异常
return 0;
}
