JAVA程序设计-答案

}

public int mileage;

private static final int TOP_SPEED = 50; abstract void alert();

public static int getTopSpeed() { return TOP_SPEED;

}

public void setCarName() { carName = \; }

public void setMileage() { mileage = 180; }

5．找出下面代码的错误部分，说明错误类型及原因，并更正之。 public class Car {

private String carName; public int mileage;

private static final int TOP_SPEED = 200; abstract void alert();

public static int getTopSpeed() { return TOP_SPEED; }

public static void setCarName() { carName = \奥迪\ }

public static void setMileage() { mileage = 180; } }

错误：因为含有抽象方法的类，必须是抽象类；静态方法只能访问静态成员。 更正：

public abstract class Car {

private String carName; public int mileage;

private static final int TOP_SPEED = 200; abstract void alert();

public static int getTopSpeed() { return TOP_SPEED; }

public void setCarName() { carName = \奥迪\;

}

public void setMileage() { mileage = 180; } }

6．下列代码不能编译的原因是：（ ）。 class A {

private int x;

public static void main(String args[]) { new B(); } class B { B() {System.out.println(x); } } }

因为在A类的main方法中,还没有A的实例就要试图生成内部类的实例。 更正如下： public class A { private int x;

public static void main(String args[]) { A a = new A(); a.new B(); }

class B { B() {

System.out.println(x);

} } }