1.请编写一个完整的Java Application程序,能够计算圆的周长和面积。要求:
1)定义点类CPoint;
2)定义圆类CCircle继承自类CPoint,类中属性包括:圆心,半径,类中方法包括:求周长perimeter()、求面积area();
3) 定义主类CCircleDemo,利用类CCircle输出一个圆的圆心,半径,周长和面积。
点类: public class CPoint { int x; int y; public CPoint(int x, int y) { this.x = x; this.y = y; } public int getX() { return x; } public void setX(int x) { this.x = x; } public int getY() { return y; } public void setY(int y) { this.y = y; } } 圆类: //圆 public class CCircle extends CPoint { private int r; private final static double PI=3.14; //构造方法 public CCircle(int x, int y,int r) { super(x, y); this.r=r; } //计算面积 public double area(){ return PI*r*r; } //计算周长 public double perimeter(){ return 2*PI*r; } public int getR() { return r; } public void setR(int r) { this.r = r; } public static double getPi() { return PI; } } 测试类: public class CCircleDemo { public static void main(String[] args) { CCircle cc=new CCircle(5, 5, 5); System.out.println("圆的信息如下:"); System.out.println("圆心点坐标:x="+cc.getX()+" y="+cc.getY()); System.out.println("圆的半径:r="+cc.getR()); System.out.println("圆的周长:"+cc.perimeter()); System.out.println("圆的面积:"+cc.area()); } }
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