摘要： abstract class A{public abstract void f(int x);public abstract void g(int x,int y);public abstract void h(double x);}class Length extends A{public void f(int x){System.out.println("这个长方体的长为12。");}public void g(int x,int y){}public void h(double x){}}class Width extends A{public void g(int 阅读全文