1.定义一个抽象类Shape,包含抽象方法求面积area(),求周长perimeter()和显示属性display()三

1.interface Shape
{
public abstract double area();
public abstract double perimeter();
public abstract double display();
}
2.class Circle implements Shape
{
int x;//横坐标
int y;//纵坐标
x09double a;//半径
x09public Circle (int x,int y,double a)//构造函数
x09{
this.x=x;
this.y=y;
x09x09this.a=a;
x09}
x09public double area()
x09{
x09x09return 3.14*a*a;
x09}
public double perimeter()
x09{
x09x09return 2*3.14*a;
x09}
public void display()
x09{
x09 System.Out.println("此圆的圆心为a("+this.x+","+this.y+")");
System.Out.println("此圆的半径为r="+this.a);
x09}
}
3.4.就不写了,与圆类似,就多了个drow()函数,你可以去找找这个函数的实现
5.public static void main(String[]args)throws IOException
{
Circle C=new Circle(2,3,5);
System.out.println("所求圆的面积S="+C.area());
System.out.println("所求圆的周长L="+C.perimeter());
C.display();
//其他的测试一样
}