类与对象在定义的Person类中添加构造方法

1. 在前面定义的Person类中添加构造方法，利用构造方法设置所有人的age属性初始值都为18。

2. 修改上题中类和构造方法，增加name属性,使得每次创建Person对象的同时初始化对象的age属性值和name属性值。

+setAge(i: int)

+getAge(): int

【输入形式】无
【输出形式】控制台输出
【样例输入】无
【样例输出】

name:tom, age:18

name:jerry, age:18

//在前面定义的Person类中添加构造方法，利用构造方法设置所有人的age属性初始值都为18。

//修改上题中类和构造方法，增加name属性,使得每次创建Person对象的同时初始化对象的age属性值和name属性值。
class Person{
  int age;
  String name;
  public Person(){
    age = 18;
  }
   public Person(int age,String name){
    this.age = age;
    this.name = name;
  }
  public setAge(int age){this.age = age;}
  public getAge(){return age;}
}

class Person{
      private:
          int age;
          String name;
  public:
          Person() {age = 18;}
          Person(String n,int a) {name = n;age = a;}
          void setAge(int a) {age = a;}
          int getAge() {return age;}
          void setName(String n) {name = n;}
          String getName() {return name;}
}

试试，有问题继续沟通交流。

public class Person {
    private String name;
    private int age;

    public Person(String name) {
        this.name = name;
        this.age = 18;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString(){
        return "name:"+name+",age:"+age;
    }

    public static void main(String[] args) {
        Person person1=new Person("tom");
        Person person2=new Person("jerry");
        System.out.println(person1);
        System.out.println(person2);
    }
}

class Person{
  int age=18;
  String name;
  public setAge(int age){this.age = age;}
  public getAge(){return age;}
  public setName(String name){this.name = name;}
  public getName(){return name;}
    //包含一个带参的构造器和一个不带参的构造器
    public Person(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }
  public Person() {
        super();
    }
}

//调用
public class ReflectionTest {
    public void testNewInstance(){

        Person per = new Person();
        System.out.println(per);
        
        Person p = new Person("tom",18);
        System.out.println(p);
    }
}