浅析C#值传递与引用值传递

using UnityEngine;
using System.Collections;

public class TypePassing : MonoBehaviour {
    public Dog dog = new Dog (1, "xiaobai") ;
    //调用默认构造函数给struct里所有字段一个缺省值，对dog来说是null
    public Cat cat = new Cat ();//貌似在这里不能直接赋值dog属性
    int i = 0;
    void Start(){
        cat = new Cat (dog, 1, "xiaohua");
        ParameterPass (dog);
        Debug.Log (dog.number + dog.name);//1xiaobai
        ParameterPass (out dog);
        Debug.Log (dog.number + dog.name);//8yuzi
        ParameterPass (i);
        Debug.Log ("i="+i);//i=0
        ParameterPass (ref i);
        Debug.Log ("i="+i);//i=2
        Debug.Log (cat.name + cat.number + cat.dog.name);//xiaohua1xiaobai
        ParameterPass (cat);
        Debug.Log (cat.name + cat.number + cat.dog.name);//xiaohua1xiaobai
    }
    //不带ref的引用传递，只有在改变对象的字段时才会影响原来对象
    //推测是一个新的变量指向原来的地址,对值类型直接copy一份过来
    void ParameterPass(Dog dog){
        dog = new Dog(6,"xiaolong");
    }
    //使用ref的传递是彻底的引用传递，无论对参数进行什么操作都将影响原来对象
    /*void ParameterPass(ref Dog dog){
        dog = new Dog(7,"feizi");
    }*/
    //out与ref类似，不做任何复制，直接传递引用
    //out与ref不能重载，与不带out、ref的方法能重载
    void ParameterPass(out Dog dog){
        dog = new Dog(8,"yuzi");
    }
    void ParameterPass(int i){
        i = 1;
    }
    void ParameterPass(ref int i){
        i = 2;
    }
    void ParameterPass(Cat cat){
        cat.name = "simao";
        cat.dog = new Dog(8,"yuzi");
        cat.dog.name = "feizhu";
    }
}

public class Dog{
    public int number;
    public string name;
    public Dog(int number, string name){
        this.number = number;
        this.name = name;
    }
}
public struct Cat{
    public Dog dog;
    public int number;
    public string name;
    public Cat(Dog dog,int number,string name){
        this.dog = dog;
        this.number = number;
        this.name = name;
    }
}