- 技术人生
- 继承方法求圆和矩形面积
//Area.java
public abstract class Area{
public abstract double area();
}
//RoundArea.java
public class RoundArea extends Area {
private double radii;
RoundArea(){}
RoundArea(double r){
radii=r;
}
public double area() {
return Math.PI*radii*radii;
}
}
//RectArea.java
public class RectArea extends Area {
private double length;
private double width;
RectArea()
{}
RectArea(double l,double w){
length=l;
width=w;
}
public double area() {
return length*width;
}
}
//ImpleArea.java具体实现类
import javax.swing.JOptionPane;
import java.util.StringTokenizer;
public class ImpleArea {
public static void main(String a[]) {
String radiiString = JOptionPane.showInputDialog("Enter the radii of Round: ");
double number_radii = Double.parseDouble(radiiString);
RoundArea round = new RoundArea(number_radii);
JOptionPane.showMessageDialog(null,"The area of round = "+round.area());
String lengthAndWidth_String = JOptionPane.showInputDialog("Enter the length and the width of Rectangle: ");
StringTokenizer length_Width_String=new StringTokenizer(lengthAndWidth_String);
//StringTokenizer类可以把字符串分成多个单词。该类在标准的java.util软件包中。
double number_length = Double.parseDouble(length_Width_String.nextToken());
double number_width=Double.parseDouble(length_Width_String.nextToken());
RectArea rectangle = new RectArea(number_length, number_width);
JOptionPane.showMessageDialog(null, "The area of rectangle =" + rectangle.area());
}
}
