C#计算一段程序运行时间的三种方法

C#计算一段程序运行时间的三种方法

亲测有效~

直接代码：
第一种方法利用System.DateTime.Now

 1         public static void SubTest()
 2         {
 3             DateTime beforeDT = System.DateTime.Now;
 4             int[] a = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
 5             //Shuffle(a) is the function you want to test.
 6             Shuffle(a);
 7             DateTime afterDT = System.DateTime.Now;
 8             TimeSpan ts = afterDT.Subtract(beforeDT);
 9             Console.WriteLine("DateTime costed for Shuffle function is: {0}ms",ts.TotalMilliseconds);
10         }

第二种用Stopwatch类(System.Diagnostics)

public static void SubTest() {
    Stopwatch sw = new Stopwatch();
    sw.Start();
    //Shuffle(a) is the function you want to test.
    int[] a = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
    Shuffle(a);
    sw.Stop();
    TimeSpan ts = sw.Elapsed;
    Console.WriteLine("DateTime costed for Shuffle function is: {0}ms", ts.TotalMilliseconds);
}

第三种用API实现：个人感觉以秒为单位来计算程序耗时，数量级有点大了，还是推荐前面两种毫秒级别的……

 1         [System.Runtime.InteropServices.DllImport("Kernel32.dll")]
 2         static extern bool QueryPerformanceCounter(ref long count);
 3         [System.Runtime.InteropServices.DllImport("Kernel32.dll")]
 4         static extern bool QueryPerformanceFrequency(ref long count);  
 5         public static void SubTest()
 6         {
 7             long count = 0;
 8             long count1 = 0;
 9             long freq = 0;
10             double result = 0;
11             QueryPerformanceFrequency(ref freq);
12             QueryPerformanceCounter(ref count);
13             //Shuffle(a) is the function you want to test.
14             int[] a = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
15             Shuffle(a);
16             QueryPerformanceCounter(ref count1);
17             count = count1 - count;
18             result = (double)(count) / (double)freq;
19             //Note:The result is counted by second.
20             Console.WriteLine("DateTime costed for Shuffle function is: {0} s", result);
21         }

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作者：传说中的汽水枪 
来源：CSDN 
原文：https://blog.csdn.net/xzjxylophone/article/details/6832160 
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