Question

JAVA中怎么定义一个圆类 要求如下

Answer 1

定义圆类Circle要求：
圆上某一点包含俩坐标的类Point(x, y) 半径centert

public class Circle {
Point center;
double r;
public Circle(Point center, double r){
this.center = center;
this.r = r;
}
public Circle(int x, int y, double r){
// 在一个类构造方法悄脊内部可用this(参数列表)调用该类其余构造方猛没法
// this(参数列表)必须写在构造方法第一行
this(new Point(x, y), r);
}
/枝运纳/计算圆面积
public double area(){
return Math.PI*this.r*r;
}

}
class Point{
int x;
int y;
public Point(int x, int y){
this.x = x;
this.y = y;
}
}