20 C++ - 面向对象程序设计案例

1. 设计立方体类

设计立方体类(Cube)，求出立方体的面积( 2*a*b + 2*a*c + 2*b*c )和体积( a * b * c)，分别用全局函数和成员函数判断两个立方体是否相等。

//立方体类
class Cub{
public:
	void setL(int l){ mL = l; }
	void setW(int w){ mW = w; }
	void setH(int h){ mH = h; }
	int getL(){ return mL; }
	int getW(){ return mW; }
	int getH(){ return mH; }
	//立方体面积
	int caculateS(){ return (mL*mW + mL*mH + mW*mH) * 2; }
	//立方体体积
	int caculateV(){ return mL * mW * mH; }
	//成员方法
	bool CubCompare(Cub& c){
		if (getL() == c.getL() && getW() == c.getW() && getH() == c.getH()){
			return true;
		}
		return false;
	}
private:
	int mL; //长
	int mW; //宽
	int mH; //高
};

//比较两个立方体是否相等
bool CubCompare(Cub& c1, Cub& c2){
	if (c1.getL() == c2.getL() && c1.getW() == c2.getW() && c1.getH() == c2.getH()){
		return true;
	}
	return false;
}

void test(){
	Cub c1, c2;
	c1.setL(10);
	c1.setW(20);
	c1.setH(30);

	c2.setL(20);
	c2.setW(20);
	c2.setH(30);

	cout << "c1面积:" << c1.caculateS() << " 体积:" << c1.caculateV() << endl;
	cout << "c2面积:" << c2.caculateS() << " 体积:" << c2.caculateV() << endl;

	//比较两个立方体是否相等
	if (CubCompare(c1, c2)){
		cout << "c1和c2相等!" << endl;
	}
	else{
		cout << "c1和c2不相等!" << endl;
	}

	if (c1.CubCompare(c2)){
		cout << "c1和c2相等!" << endl;
	}
	else{
		cout << "c1和c2不相等!" << endl;
	}
}

2. 点和圆的关系

设计一个圆形类（AdvCircle），和一个点类（Point），计算点和圆的关系。

假如圆心坐标为x0, y0, 半径为r，点的坐标为x1, y1：

1. 在圆上：(x1-x0)(x1-x0) + (y1-y0)(y1-y0) == r*r
2. 点在圆内：(x1-x0)(x1-x0) + (y1-y0)(y1-y0) < r*r
3. 点在圆外：(x1-x0)(x1-x0) + (y1-y0)(y1-y0) > r*r

//点类
class Point{
public:
	void setX(int x){ mX = x; }
	void setY(int y){ mY = y; }
	int getX(){ return mX; }
	int getY(){ return mY; }
private:
	int mX;
	int mY;
};

//圆类
class Circle{
public:
	void setP(int x,int y){
		mP.setX(x);
		mP.setY(y);
	}
	void setR(int r){ mR = r; }
	Point& getP(){ return mP; }
	int getR(){ return mR; }
	//判断点和圆的关系
	void IsPointInCircle(Point& point){
		int distance = (point.getX() - mP.getX()) * (point.getX() - mP.getX()) + (point.getY() - mP.getY()) * (point.getY() - mP.getY());
		int radius = mR * mR;
		if (distance < radius){
			cout << "Point(" << point.getX() << "," << point.getY() << ")在圆内!" << endl;
		}
		else if (distance > radius){
			cout << "Point(" << point.getX() << "," << point.getY() << ")在圆外!" << endl;
		}
		else{
			cout << "Point(" << point.getX() << "," << point.getY() << ")在圆上!" << endl;
		}
	}
private:
	Point mP; //圆心
	int mR; //半径
};

void test(){
	//实例化圆对象
	Circle circle;
	circle.setP(20, 20);
	circle.setR(5);
	//实例化点对象
	Point point;
	point.setX(25);
	point.setY(20);

	circle.IsPointInCircle(point);
}