题目是使用接口比较汽车速度的大小//主类public class tVehicle extends Vehicle{ public static void main(String[] args) { // TODO Auto-generated method stub Vehicle a=new Vehicle(); a.speedup(); Vehicle b=new Vehicle(); b.speedup(); b.speedup(); int a1; a1=a.speed; int b1; b1=b.speed; compare( a1, b1); }}//Vehicle类public class Vehicle implements Comparable{int speed=0;public void speedup() { speed+=10;}public void slowdown() { speed-=10;}public void showinfo() { System.out.println(speed);}public String tostring() { return "I'm a vehicle";}public void compare(int a,int b){ if(a>b) System.out.println("a速度大"); else System.out.println("b速度大");}}//接口类public interface Comparable { public void compare(int a,int b) ;}