public class Circle {
private double r;
public Circle() {
this.r = 0;
}
public Circle(double r) {
this.r = r;
}
public double getR() {
return r;
}
public void setR(double r) {
this.r = r;
}
/*
* 获取圆的面积
*/
private double getArea() {
return Math.PI*r*r;
}
/*
* 获取圆的周长
*/
private double getPerimeter() {
return Math.PI*r*2;
}
/**
* 输出
*/
public void show() {
System.out.println("圆的半径为:"+r+",周长为:"+getPerimeter()+",面积为:"+getArea());
}
}
public class Cylinder extends Circle {
private double height;
public Cylinder(double r ,double height) {
this.setR(r);
this.height = height;
}
public double getHeight() {
return height;
}
public void setHeight(double height) {
this.height = height;
}
/**
* 计算圆柱体的体积
*/
private double getVolumn() {
return Math.PI*this.getR()*this.getR()*height;
}
/**
* 显示圆柱体的体积
*/
public void showVolumn() {
System.out.println("半径为:"+this.getR()+",圆柱体的体积为:"+getVolumn() );
}
}
测试类:
public class MainTest {
public static void main(String[] args) {
Circle c = new Circle(2.0);
c.show();
Cylinder cy = new Cylinder(2.0,4.0);
cy.showVolumn();
}
}
结果:
圆的半径为:2.0,周长为:12.566370614359172,面积为:12.566370614359172
半径为:2.0,圆柱体的体积为:50.26548245743669
追问
这里的错误怎么修改啊?
追答Cylinder写在另外一个文件里
大兄弟,你也太有才了
两个类放一个文件不可以的
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