请问这个是什么错误,怎么解决,我继承的时候出现了这个问题
Implicit super constructor Rectangular() is undefined for default constructor. Must
define an explicit constructor
Implicit super constructor Rectangular() is undefined for default constructor. Must
define an explicit constructor
{
public float Area();
public float Circumference();
}
class Rectangular implements Shape
{
private float Long;
private float Wide;
public static void Sum()
{
int num = 1;
num++;
System.out.println("实例化个数为:"+num);
}
public Rectangular(float Long,float Wide)
{
this.Long=Long;
this.Wide=Wide;
}
public float Area()
{
return Long*Wide;
}
public float Circumference()
{
return Long+Long+Wide+Wide;
}
public void ShowInfo()
{
System.out.println("面积是"+Long*Wide);
System.out.println("周长是"+(Long+Long+Wide+Wide));
}
}
class Square extends Rectangular{ private float Side;
public float Area()
{
return Side*Side;
}
public float Circumference()
{
return 4*Side;
}
}
// 给你个例子,自己看吧
public interface Shape2D {
final double pi = 3.14; public abstract double area();
}class Circle implements Shape2D {
double radius; public Circle(double r) {
radius = r;
} public double area() {
return pi * radius * radius;
}
}class Rectangle implements Shape2D {
double width, height; public Rectangle(double w, double h) {
width = w;
height = h;
} public double area() {
return width * height;
}
}public class InterfaceTest {
public static void main(String[] args) {
System.out.println("Example 1:");
Rectangle rect = new Rectangle(5, 6);
System.out.println("The rect area = " + rect.area());
Circle cir = new Circle(2);
System.out.println("The cir area = " + cir.area()); System.out.println("Example 2:");
Shape2D var1, var2;
var1 = new Rectangle(5, 6);
System.out.println("The Rectangle area = " + var1.area());
var2 = new Circle(2);
System.out.println("The Circle area = " + var2.area());
}
}
import java.lang.*;interface Shape
{
public float Area();
public float Circumference();
}
public class Rectangular implements Shape
{
private float Long;
private float Wide;
public static void Sum()
{
int num = 1;
num++;
System.out.println("实例化个数为:"+num);
}
public Rectangular(float Long,float Wide)
{
this.Long=Long;
this.Wide=Wide;
}
public Rectangular()
{ }
public float Area()
{
return Long*Wide;
}
public float Circumference()
{
return Long+Long+Wide+Wide;
}
public void ShowInfo()
{
System.out.println("面积是"+Long*Wide);
System.out.println("周长是"+(Long+Long+Wide+Wide));
}
}
class Square extends Rectangular{ private float Side;
public float Area()
{
return Side*Side;
}
public float Circumference()
{
return 4*Side;
}
}
{
public float Area();
public float Circumference();
}
class Rectangular implements Shape
{
private float Long;
private float Wide;
public static void Sum()
{
int num = 1;
num++;
System.out.println("实例化个数为:"+num);
}
public Rectangular(float Long,float Wide)
{
this.Long=Long;
this.Wide=Wide;
}public Rectangular() { //缺省参数的构造器
this(0, 0);
}
public float Area()
{
return Long*Wide;
}
public float Circumference()
{
return Long+Long+Wide+Wide;
}
public void ShowInfo()
{
System.out.println("面积是"+Long*Wide);
System.out.println("周长是"+(Long+Long+Wide+Wide));
}
}
class Square extends Rectangular{ //如果Rectangular没有缺省的构造器,这里就不能Square的构造器,而且要在Square的构造器中显式调用Rectangular构造器
private float Side;
public float Area()
{
return Side*Side;
}
public float Circumference()
{
return 4*Side;
}
}