如果父类中的抽象方法是无参的，那么子类中重写的方法是不是必须也是无参的？
比如要算矩形的周长需要两个参数l和h，面积需要两个参数l和h，而圆形周长和面积只需要一个参数r。
这个时候需要怎么定义抽象方法？是不是需要再定义两次抽象方法为两个参数的和一个参数的，并且重写的方法中参数还必须和抽象方法中一样？
这是抽象父类Shape：
public abstract class Shape {
public abstract void getGirth(int a,int b);
public abstract void getArea(int a,int b);
public abstract void getGirth(int a);
public abstract void getArea(int a);
}这是子类Rectangle:
public class Rectangle extends Shape {
@Override
public void getGirth(int a,int b) {
// TODO Auto-generated method stub
System.out.println("矩形的面积为:"+(2*a+2*b));
}
@Override
public void getArea(int a,int b) {
// TODO Auto-generated method stub
System.out.println("矩形的面积为:"+a*b);
}
@Override
public void getGirth(int a) {
// TODO Auto-generated method stub
}
@Override
public void getArea(int a) {
// TODO Auto-generated method stub
}这是子类Circle:
public class Circle extends Shape {
@Override
public void getGirth(int a) {
// TODO Auto-generated method stub
System.out.println("圆形的周长为:"+(2*3.14*a));
}
@Override
public void getArea(int a) {
// TODO Auto-generated method stub
System.out.println("圆形的面积为："+3.14*a*a);
}
@Override
public void getGirth(int a, int b) {
// TODO Auto-generated method stub
}
@Override
public void getArea(int a, int b) {
// TODO Auto-generated method stub
}测试类Test:
public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
Shape a = new Rectangle();
Shape b = new Circle();
a.getGirth(3, 4);
a.getArea(3, 4);
b.getGirth(3);
b.getArea(3);
}运行结果:
矩形的面积为:14 矩形的面积为:12 圆形的周长为:18.84 圆形的面积为：28.259999999999998
想问下有没有更简便点的办法？
首先重写子类的方法必须和被继承的父类的方法相同
//父类
public class Shape {
public void getArea(){
System.out.println("图形的面积");
}
public void getGirth(){
System.out.println("图形的周长");
}
}
//圆形子类
public class Circle extends Shape {
int r=3;
public void getArea(){
double area=3.14*r*r;
System.out.println("圆形的面积"+area);
}
public void getGirth(){
double girth=2*3.14*r;
System.out.println("圆形的周长"+girth);
}
}
//方形子类
public class Rectangle extends Shape {
int a=2;
int b=4;
public void getArea(){
double area=a*b;
System.out.println("方形的面积"+area);
}
public void getGirth(){
double girth=2*(a+b);
System.out.println("圆形的周长"+girth);
}
}
//测试类
public class Initial {
public static void main(String[] args) {
// TODO Auto-generated method stub
Circle circle= new Circle();
circle.getArea();
circle.getGirth();
Rectangle rectangle= new Rectangle();
rectangle.getArea();
rectangle.getGirth();
}
}这是我写的。。。。
//父类
public abstract class Shape {
public abstract double perimeter(double i,double j);
public abstract double Area(double m,double n);
}
//子类Circle
public class Circle extends Shape {
@Override
public double perimeter(double i, double j) {
// TODO Auto-generated method stub
double p = 2 * i * j;
return p;
}
@Override
public double Area(double m, double n) {
// TODO Auto-generated method stub
double s = m * n * n;
return s;
}
}
//子类Rectangle
public class Rectangle extends Shape {
@Override
public double perimeter(double i,double j) {
// TODO Auto-generated method stub
double p = 2*(i+j);
return p ;
}
@Override
public double Area(double m,double n) {
// TODO Auto-generated method stub
double s = m*n;
return s;
}
}
//测试类
import java.util.*;
public class Inital {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner scanner = new Scanner(System.in);
Shape a = new Rectangle();
Shape b = new Circle();
for( int i =0 ;i <= 1; i++){
double m=0;
double n=0;
if(i == 0){
System.out.println("count Rectangle,Please input length and width");
System.out.println("length:");
m = scanner.nextDouble();
System.out.println("width：");
n = scanner.nextDouble();
double p = a.perimeter(m, n);
double s = a.Area(m, n);
System.out.println("Rectangle's perimeter :"+p);
System.out.println("Rectangle's Area:"+s);
}
if(i == 1){
System.out.println("count Circle,Please input radius");
// System.out.println("PI:");
// m = scanner.nextDouble();
System.out.println("radius：");
n = scanner.nextDouble();
double p = b.perimeter(Math.PI, n);
double s = b.Area(Math.PI, n);
System.out.println("Circle's perimeter :"+p);
System.out.println("Circle's Area:"+s);
}
}
}
}可以使用可变长参数试试