假设有若干 (如10）个Circle，Rectangle和Square形状，计算总面积

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假设有若干 (如10）个Circle，Rectangle和Square形状，计算总面积

java编程

java类求N个图形的面积和

应用纯虚函数的使用，定义几个派生类如三角形，矩形，圆形等，求出所有形状的总面积。

一、假设有若干 (如10）个Circle，Rectangle和Square形状，计算总面积

package OctoberTwentyfour;

abstract class Shape{

protected String type;

protected double area, perim;

public abstract void computeArea();

public String toString()

{ return type + ":Area = " + area + "Perimeter = " + perim;

}

}//父类

package OctoberTwentyfour;

class Rectangle extends Shape{

protected double width, height;

public Rectangle(double _width, double _height)

{ type = "Rectangle";

width = _width;

height = _height;

}

public void computeArea()

{ area = width * height; }

public void computePerimeter()

{ perim = 2*width + 2*height; }

public String toString()

{ return super.toString() + "Width = " + width + "Height = " + height;

}

}//矩形子类

package OctoberTwentyfour;

class Circle extends Shape

{ protected double radius;

public Circle(double _radius)

{ type = "Circle";

radius = _radius;

}

public void computeArea()

{ area = Math.PI * radius * radius; }

public void computePerimeter()

{ perim = 2.0 * Math.PI * radius; }

public String toString()

{ return super.toString() +"Radius = " + radius;

}

}

//圆子类

package OctoberTwentyfour;

class Square extends Rectangle

{ public Square(double _side)

{ super(_side, _side);//重写父类方法super

type = "Square";

}

}

//继承于矩形的正方形子类

package OctoberTwentyfour;

public class ShapeTest

{ public static void main(String args[])

{ Shape shapes[] = new Shape[10];

double total_area=0.0;

int k=0;

for (int i=0; i<shapes.length; i++ ){

k=(int)Math.ceil(Math.random()*3);

System.out.println("k is :"+k);

switch (k) {

case 1: shapes[i]=new Circle(Math.random()*10);

break;

case 2: shapes[i]=new Rectangle(Math.random()*10, Math.random()*10);

break;

case 3: shapes[i]=new Square(Math.random()*10);

break;

}

}

for (int i = 0; i < shapes.length; i++) {

shapes[i].computeArea();

total_area+=shapes[i].area;

}

System.out.println("Total area is :"+total_area);

}

}

//测试

运行结果图

一、java编程

//亲手为你所写

abstract class Shape{
public abstract double area();
}

class Circle extends Shape{
int r;
final double pi = 3.14;

public Circle(int r){
this.r= r;

}
public double area(){
return pi*r*r;
}
}

class Rectang extends Shape{
int w;
int h;

public Rectang(int w,int h){
this.w = w;
this.h = h;
}

public double area(){
return w*h;
}
}

public class Test{
public static void main(String[] args){
double area_total=0;
int i;

Circle c1 = new Circle(2);
Circle c2 = new Circle(3);

Rectang rg1 = new Rectang(2,3);
Rectang rg2 = new Rectang(3,4);

Shape sshape[] = {c1,c2,rg1,rg2};
for (i=0; i *pvec )
{
// ...
for ( ; it != end_it; ++it )
{
Query *pq = *it;
// ...
delete pq;
}
}
为了使函数能够正确执行，在应用delete 表达式时，必须调用pq 指向的动态类型的析构函数。为此，必须把Query 类析构函数声明为虚拟的。