我正在尝试编写一个利用java的Abstract类特性的程序.第63行我得到了一个"非法的表达式开始"错误,它声明了公共类AbstractCar.任何人都可以解释为什么我收到此错误以及如何纠正它.先感谢您
public class AbstractCar {
public static final void main(String args[]) {
abstract class Vehicle {
//subclasses will inherit an attribute
int maxSpeed;
//subclasses must implement this method
//(otherwise they have to be declared as abstract classes)
abstract void showMaxSpeed();
//subclass will have this method (through inheritance) as is (default implementation)
//or they may implement their own implementation (override a method)
int getWheelsNumber() {
return 4;
}
}
/**Car IS-A Vehicle*/
class Car extends Vehicle {
public Car() {
maxSpeed …为什么在这个类(StringWriter,PrintWriter)方法close中没有像javadoc中提到的那样有效？
据我所知,简单的没有实现.但为什么？
只是执行codecademy课程,当我运行代码时,一切都有效,除了这个if/else语句.当它到达那个时,无论我为userAnswer提示输入什么,我只是得到'if'输出.有人可以解释原因吗？一直在读这个东西100x,答案不是跳出来的.万分感谢.
var userAnswer = prompt("Do you want to race Bieber on stage?");
if(userAnswer="yes") {
console.log("You and Bieber start racing. It's neck and neck! You win by a shoelace!")
} else {
console.log("Oh no! Bieber shakes his head and sings 'I set a pace, so I can race without pacing.'")
}