(1)根据下面的要求实现圆类Circle。
1.圆类Circle的成员变量:radius表示圆的半径。
2.圆类Circle的方法成员:
Circle():构造方法,将半径置0
Circle(double r):构造方法,创建Circle对象时将半径初始化为r
double getRadius():获得圆的半径值
double getPerimeter():获得圆的周长
void disp():将圆的半径和圆的周长,圆的面积输出到屏幕
(2)继承第一题中的圆Circle类,派生圆柱体类Cylinder。要求如下:
1.圆柱体类Cylinder的成员变量:height表示圆柱体的高。
2.圆柱体类Cylinder的成员方法:
Cylinder(double r,double h)构造方法,创建Cylinder对象时将圆半径初始化为r,圆柱体高初始化为h。
double getHeight():获得圆柱体的高
double getVol():获得圆柱体的体积
void dispVol():将圆柱体的体积输出到屏幕
3.按照第二题的Cylinder类,接上键盘的输入值作为圆的半径和圆柱体的高,计算圆柱体的体
package work4;
public class Circle {
private double radius;
public Circle (double r) {
radius=r;
}
public double getRadius() {
return radius;
}
public void setRadius(double radius) {
this.radius = radius;
}
public double getPerimeter() {
return 2*Math.PI*radius;
}
public double getArea() {
return Math.PI*Math.pow(radius,2);
}
public static void main(String[] args) {
Circle total=new Circle(16);
System.out.println("圆的半径为:"+total.radius);
System.out.println("圆的周长为:"+total.getPerimeter());
System.out.println("圆的面积为:"+total.getArea());
}
}
class Cylinder extends Circle { private double height; public Cylinder(double r,double h) { super(r); height = h; } public double getHeight() { return height; } public double getVol() { return getArea()*height; } public void dispVol() { System.out.println("圆柱的体积为:"+getVol()); } } public class jichengyuan { public static void main(String[] args) { Cylinder der = new Cylinder(1.0,2.0); der.dispVol(); } }
public class Cylinder extends Circle { private double height; public Cylinder(double h, double r) { super(r); this.setHeight(height); } public double getHeight() { return height; } public void setHeight(double height) { this.height = height; } public double getVol() { return super.getArea() * height; } public static void main(String[] args) { Cylinder cy = null; cy = new Cylinder(0, 0); cy.setRadius(7.0); cy.height = 8.0; System.out.println("半径:" + cy.getRadius()); System.out.println("高:" + cy.getHeight()); System.out.println("体积:" + cy.getVol()); } }