没有实例化
package math;
public class all {
public abstract class shape {
public abstract void area();
public abstract void perimeter();
}
public abstract class circle extends shape {
double r = 2.2;
public void area(){
System.out.println("circle area is "+3.14*r*r);
}
public void perimeter(){
System.out.println("circle perimete is "+2*r*3.14);
}
}
public abstract class rectangle extends shape {
double a=1.0;
double b=1.0;
public void area(){
System.out.println("rectangle ares is"+a*b);
}
public void perimeter(){
System.out.println("recrangle perimeter is "+2*(a+b));
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
shape area1 = new circle();//这里显示错误，Cannot instantiate the type circle
area1.perimeter();
area1.area();
shape area2 = new rectangle();//这里显示错误，Cannot instantiate the type rectangle
area2.perimeter();
area2.area();
}
}问一下这个情况该怎么解决。找不到解决方法，谢谢
