2018年10.21课后作业一

package trackobjectnum;

public class ObjectNum {
    private static int n = 0;
    public ObjectNum() {
        n = n + 1;
    }
    public static int getNum() {
        return n;
    }
   
    public static void main(String[] args) {
        ObjectNum o1 = new ObjectNum();
        ObjectNum o2 = new ObjectNum();
        ObjectNum o3 = new ObjectNum();
        ObjectNum o4 = new ObjectNum();
        System.out.println("已生成对象个数为：" + ObjectNum.getNum());
    }
}