方法的参数传递机制

方法的参数传递机制

考点

1. 形参是基本数据类型

• 传递数据值

2. 实参是引用数据类型

• 传递地址值
• 特殊的类型：String、包装类对象不可变性

例题

下面代码的运行结果是：

public class Exam{

  public static void main(String[] args){
    int i = 1;
    String str = "hello";
    Integer num = 200;
    int[] arr = {1,2,3,4,5};
    MyData my = new MyData();

    change(1,str,num,arr,my);

    System.out.println("i = " +i);
    System.out.println("str = " +str);
    System.out.println("num = " +num);
    System.out.println("arr = " +Array.toString(arr));
    System.out.println("my.a = " +my.a);
  }
  
  public  public static void change(){
     j += 1;
     s += "world";
     n += 1;
     a[0] += 1;
     m.a += 1;
  }

}

class MyData{
  int a = 10;
}

答案

i = 1;
str = hello;
num = 200;
arr = {2,2,3,4,5};
my.a = 11;

解析