java圆的类的定义

A. java 定义一个圆类Circle，就解

publicclassCircle{
//圆的半径
privatedoubleradius;

//求圆的面积
publicdoublefindArea(){
returnMath.PI*radius*radius;
}

publicdoublegetRadius(){
returnradius;
}

publicvoidsetRadius(doubleradius){
this.radius=radius;
}
}

测试类自己去写。

B. JAVA中怎么定义一个圆类 要求如下

public class Circle {
private double r;

public Circle(double r) {
this.r = r;
}

public double getR() {
return r;
}

public void setR(double r) {
this.r = r;
}

/**
* 面积
*
* @return
*/
public double getArea() {
return Math.PI * Math.pow(r, 2);
}

/**
* 周长
*
* @return
*/
public double getLong() {
return Math.PI * r * 2;
}
}class Cylinder extends Circle {
private double h;

public Cylinder(double r, double h) {
super(r);
this.h = h;
}

public double getH() {
return h;
}

public void setH(double h) {
this.h = h;
}

/**
* 体积 = 底面积*高
*
* @return
*/
public double getVolume() {
return super.getArea() * h;
}

/***
* 表面积=测面积+2个底面积
*
* @return
*/
public double getSurfacearea() {
return super.getLong() * h + 2 * super.getArea();
}

}
测试代码就不写了

C. JAVA定义圆形类。

public class Circle{
private double r;

public void setR(double r){
this.r=r;
}

public double getArea(){
return Math.PI*r*r;
}

public double getPerimeter(){
return 2*Math.PI*r;
}
}

public class TestCircle{
public static void main(String [] args){
//两个不同对象
Circle circle1 = new Circle();
Circle circle2 = new Circle();
//设置不同半径
circle1.setR(2);
circle2.setR(3);
//显示结果
system.out.println("半径为2的圆面积是"+circle1.getArea()+", 周长是"+circle1.getPerimeter());
system.out.println("半径为3的圆面积是"+circle2.getArea()+", 周长是"+circle2.getPerimeter());
}
}

D. 急求Java代码，定义一个Circle(圆类型）

public class Exam
{
public static void main(String[] args)
{
Circle c=new Circle(3,4,5);
System.out.printf("圆心：(%f,%f)，半径：%f，面积：%f",c.x,c.y,c.r,c.countArea());
}
}

class Circle
{
public Circle()
{
this(0,0,0);
}
public Circle(double x,double y,double r)
{
this.x=x;
this.y=y;
this.r=r;
}
public double countArea()
{
return Math.PI*r*r;
}
/*private*/public double x,y,r;
}

E. java编程:定义一个圆circle类,包含如下内容

代码如下：

importjava.util.Scanner;

classCircle{
	
	privatedoubleradius;

	publicCircle(doubleradius){
		this.radius=radius;
	}

	publicdoublegetRadius(){
		returnradius;
	}

	publicvoidsetRadius(doubleradius){
		this.radius=radius;
	}
	
	publicdoublegetArea(){
		returnMath.PI*radius*radius;
	}
	
	publicdoublegetPerimeter(){
		return2*Math.PI*radius;
	}
}

publicclassApp{
	
	publicstaticvoidmain(String[]argv){
		
		Scannerscanner=newScanner(System.in);
		
		System.out.print("请输入圆半径：");
		
		doubler=scanner.nextDouble();
		
		
		Circlec=newCircle(r);
		
		System.out.println("面积："+c.getArea()+"，周长："+c.getPerimeter());
	}
}

运行结果：