第八次作业

lass Person1{
    private String name;
    private static int count;
    public Person1() {
        count++;
        this.name = "NONAME - " + count;
    }
    public Person1(String name) {
        this.name = name;
    }
    public String getInfo() {
        return "姓名:" + this.name;
    }
}
public class C {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println(new Person1().getInfo());
        System.out.println(new Person1("A").getInfo());
        System.out.println(new Person1("B").getInfo());
        System.out.println(new Person1().getInfo());
    }

}

class Person2{
    private String name;
    private static int count;
    public Person2() {
        count++;
        System.out.println("产生了" + count + "个实例化");
    }
    public String getInfo() {
        return "姓名:" + this.name;
    }
}
public class V {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        new Person2();
        new Person2();
        new Person2();
        new Person2();
        new Person2();
    }

}

package zuoye;
class Person{
    private String name;
    private int age;
    static String city =  "A城";
    public Person(String name,int age) {
        this.name = name;
        this.age = age;
    }
    public String getInfo() {
        return "姓名:" + this.name + ",年龄:" + this.age + ",城市:" + city;
    }
}
public class StaticDemo02 {
    public static void main(String[] args) {
        Person per1 = new Person("张三",30);
        Person per2 = new Person("李四",31);
        Person per3 = new Person("王五",30);
        System.out.println("======修改信息之前======");
        System.out.println(per1.getInfo());
        System.out.println(per2.getInfo());
        System.out.println(per3.getInfo());
        System.out.println("======修改信息之后======");
        Person.city = "B城";
        System.out.println(per1.getInfo());
        System.out.println(per2.getInfo());
        System.out.println(per3.getInfo());
        
    }

}

class Single{
    private static Single instance = new Single();
    private Single() {
    }
    public static Single getInstance() {
        return instance;
    }
    public void print() {
        System.out.println("hello world!!!");
    }
}
public class B {
    public static void main(String[] args) {
        Single s = null;
        s = Single.getInstance();
        s.print();
    }

}