新手报道,初学问题!????求助!

Question

我是初学.net的,,希望各位多多帮助,,但现在碰到一个问题,,没搞懂.
题目,,测试采用装箱和不装箱两种情况哪种情况的运行效率更高????
请高手给段代码,谢谢!

Answer 1

int i=0;
//不装箱
for(int k = 0 ; k< 100000000; k++)
{
  i += k;
}
//装箱
for(int k = 0 ; k< 100000000; k++)
{
  object tmp = (object)i;
  tmpi = Int32.Parse(tmp);
  tmpi += k;
}

Answer 2

使用
DateTime.Now
计时如上面例子的一部分:
DateTime BeginTime=DateTime.Now,EndTime=DateTime.Now;
//不装箱
BeginTime=DateTime.Now;
for(int k = 0 ; k< 100000000; k++)
{
i += k;
}
EndTime=DateTime.Now;
Console.WriteLine(EndTime-BeginTime);

Answer 3

写了个完整的,,,,在"Snippet Compiler"下测试了.....using System;namespace iColor{
public class MyClass
{
public static void Main(string[] args)
{
int[] intArray1=new int[5000000];
int[] intArray2=new int[5000000];
object[] objArray=new object[5000000];
            DateTime bTime=DateTime.Now,eTime=DateTime.Now;
            //...
for(int i=0;i<intArray1.Length;i++){
intArray1[i]=i;
}
            //Count...
for(int count=1;count<=5;count++){
                Console.WriteLine("Count {0}",count);
                bTime=DateTime.Now;
                for(int i=0;i<intArray1.Length;i++){
                    objArray[i]=intArray1[i];
                }
                eTime=DateTime.Now;
                Console.WriteLine("ZhuangXiang Time:\n"+(eTime-bTime));
                bTime=DateTime.Now;
                for(int i=0;i<intArray1.Length;i++){
                    intArray2[i]=intArray1[i];
                }
                eTime=DateTime.Now;
    Console.WriteLine("Bu ZhuangXiang Time:\n"+(eTime-bTime));
}
Console.Read();
}
}
}
--------------
Count 1
ZhuangXiang Time:
00:00:01.3519440
Bu ZhuangXiang Time:
00:00:00.1001440
Count 2
ZhuangXiang Time:
00:00:01.7124624
Bu ZhuangXiang Time:
00:00:00.0801152
Count 3
ZhuangXiang Time:
00:00:01.6323472
Bu ZhuangXiang Time:
00:00:00.0801152
Count 4
ZhuangXiang Time:
00:00:02.3033120
Bu ZhuangXiang Time:
00:00:00.0701008
Count 5
ZhuangXiang Time:
00:00:01.6523760
Bu ZhuangXiang Time:
00:00:00.0701008

Answer 4

using System;namespace Box
{
class Box
{
#region//upBox()装箱用时
private static void upBox()
{
int[] sourceArray=new int[5000000];
object[] targetArray=new Object[5000000];
DateTime beginTime=DateTime.Now,endTime;
for(int i=0;i<5000000;i++)
{
targetArray[i]=(object)sourceArray[i];
}
for(int i=0;i<5000000;i++)
{
sourceArray[i]=(int)targetArray[i];
}
endTime=DateTime.Now;
Console.WriteLine("装箱用时:{0}",endTime-beginTime);
}
#endregion
#region//notUpBox()不装箱用时
private static void notUpBox()
{
int[] sourceArray=new int[5000000];
int[] targetArray=new int[5000000];
DateTime beginTime=DateTime.Now,endTime;
for(int i=0;i<5000000;i++)
{
targetArray[i]=sourceArray[i];
}
for(int i=0;i<5000000;i++)
{
sourceArray[i]=targetArray[i];
}
endTime=DateTime.Now;
Console.WriteLine("不装箱用时:{0}",endTime-beginTime);
}
#endregion
[STAThread]
    #region//主方法
static void Main(string[] args)
{
upBox();
notUpBox();  
}
#endregion
}
}