public class     Vehicle{
    double speed=0;
    int power=0;
    void speedUp(int x){
        speed+=x;
    }
    void speedDown(int x){
        speed-=x;
    }
    void setPower(int x){
        power=x;
    }
    int getPower(){
        return(power);
    }
    double gerSpeed(){
        return(speed);
    }
}
public class User{
    public static void main(String args[]){
        Vehicle car1,car2;
        car1=new Vehicle();car2=new Vehicle();
        car1.setPower(128);car2.setPower(76);
        System.out.println("car1:"+car1.power);System.out.println("car2:"+car2.power);
        car1.speedUp(80);car2.speedUp(80);
        System.out.println("car1:"+car1.speed);System.out.println("car2:"+car2.speed);
        car1.speedDown(10);car2.speedDown(20);
        System.out.println("car1:"+car1.speed);System.out.println("car2:"+car2.speed);
    }
 } 错误提示 Vehicle must be defined User.java

class  Vehicle{
    double speed=0;
    int power=0;
    void speedUp(int x){
        speed+=x;
    }
    void speedDown(int x){
        speed-=x;
    }
    void setPower(int x){
        power=x;
    }
    int getPower(){
        return(power);
    }
    double gerSpeed(){
        return(speed);
    }
}
public class User{
    public static void main(String args[]){
        Vehicle car1,car2;
        car1=new Vehicle();car2=new Vehicle();
        car1.setPower(128);car2.setPower(76);
        System.out.println("car1:"+car1.power);System.out.println("car2:"+car2.power);
        car1.speedUp(80);car2.speedUp(80);
        System.out.println("car1:"+car1.speed);System.out.println("car2:"+car2.speed);
        car1.speedDown(10);car2.speedDown(20);
        System.out.println("car1:"+car1.speed);System.out.println("car2:"+car2.speed);
    }
}
你的文件名，应该定义为User.java