ref out 和没加这2个参数的区别

一、没加入参数例子

 

using System;

class App
{
    public static void UseRef( int i)
    {
        i += 100;
        Console.WriteLine("i = {0}", i);
    }

    static void Main()
    {
        int i = 10;

        // 查看调用方法之前的值
        Console.WriteLine("Before the method calling: i = {0}", i);

        UseRef(i);

        // 查看调用方法之后的值
        Console.WriteLine("After the method calling: i = {0}", i);
        Console.Read();
    }
}


结果如下
Before the method calling: i = 10
i = 110
After the method calling: i = 10

 

 

二、ref参数

 

using System;

class App
{
    public static void UseRef(ref int i)
    {
        i += 100;
        Console.WriteLine("i = {0}", i);
    }

    static void Main()
    {
        int i = 10;

        // 查看调用方法之前的值
        Console.WriteLine("Before the method calling: i = {0}", i);

        UseRef(ref i);

        // 查看调用方法之后的值
        Console.WriteLine("After the method calling: i = {0}", i);
        Console.Read();
    }
}


结果如下：

Before the method calling: i = 10
i = 110
After the method calling: i = 110

 

 

三、out参数

 

using System;

class App
{
    public static void UseRef(out int i,int j)
    {
        i = 100;
        Console.WriteLine("i+j = {0}", i+j);
    }

    static void Main()
    {
        int i;

        // 查看调用方法之前的值
        //Console.WriteLine("Before the method calling: i = {0}", i);

        UseRef(out i,1);

        // 查看调用方法之后的值
        Console.WriteLine("After the method calling: i = {0}", i);
        Console.Read();
    }
}

结果如下：

i+j = 101
After the method calling: i = 100