其他内容参见 JAVA学习记录总贴 
本期是oop的简单练习，确实都很简单，主要负责熟手 
第一题
public static void main(String[] args) {
    Car c = new Car();
    Car car = new Car(100);
    System.out.println(c);
    System.out.println(car);
}
​
class Car {
    double price = 10;
    static String color = "white";
​
    public String toString() {
        return price + "\t" + color;
    }
​
    public Car(){
        this.price = 9;
        ...