详解C#中的out和ref

//主函数
 static void Main(string[] args)
 {
  //定义两个实参n1和n2，并初始化
  int n1 = 10, n2 = 20;
  Console.WriteLine("交换前n1和n2的值");
  Console.WriteLine("n1={0},n2={1}", n1, n2);//n1=10,n2=20
  Swap(n1,n2);
  Console.WriteLine("交换后n1和n2的值");
  Console.WriteLine("n1={0},n2={1}",n1,n2);//n1=10,n2=20
  Console.Read();
 }
 /// <summary>
 /// 交换两个变量的值
 /// </summary>
 /// <param name="n1">形参n1</param>
 /// <param name="n2">形参n2</param>
 static private void Swap(int t1,int t2)
 {
  int temp;
  temp =t1;
  t1 =t2;
  t2 = temp;
 }

// Cpplus.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
//主函数
int _tmain(int argc, _TCHAR* argv[])
{
 void Swap(int *x, int *y);
 int n1 = 10, n2 = 20;
 printf("交换前n1和n2的值\n");
 printf("%d,%d\n", n1, n2);
 Swap(&n1,&n2);
 printf("交换后n1和n2的值\n");
 printf("%d,%d",n1,n2);
 getchar();
 return 0;
}
//交换函数
void Swap(int *x, int *y)
{
 int temp = *x;
 *x = *y;
 *y = temp;
}

//主函数
 static void Main(string[] args)
 {
  int n1, n2;
  Console.WriteLine(GetSum(out n1,out n2));
  Console.Read();
 }
 //out参数
 static public int GetSum(out int numberFirst,out int numberSecond)
 {
  numberFirst = 10;
  numberSecond = 3;
  return numberFirst + numberSecond;
 }

//如下两个方法可以重载
public void getNumer(int num){}
public void setTime(out int num){num=10;}
//如下两个方法不能重载
public void getNumer(ref int num){num=10;}
public void setTime(out int num){num=10;}

//主函数
 static void Main(string[] args)
 {
  int n1=1, n2=3;
  Console.WriteLine(refGetSum(ref n1,ref n2));
  Console.Read();

 } 
 //ref参数
 static public int refGetSum(ref int numberFirst, ref int numberSecond)
 {
  numberFirst = 10;
  numberSecond = 3;
  return numberFirst + numberSecond;
 }