¤ C# Performance - Switch vs If-Then ¤

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mteric
Active Poster

Joined: 23 Aug 2006
Posts: 116
Location: Montana, USA

Coming from the C/C++ world, I've always used switch statements sparingly because of the slight performance hit versus using if-then statements. But after running several quick tests (like the quick-and-dirty one below), it seems that in C#, the Visual Studio compiler is able to optimize the switches so that they're faster than using if-then statements.

Code:

             int iBegin = Environment.TickCount;

             for (int x = 0; x < 1000000000; ++x)
             {
                 int i = 1;
                 switch (i)
                 {
                     case 0:
                         break;

                     case 1:
                         break;

                     default:
                         break;
                 }
             }

             int iEnd = Environment.TickCount;
             int iTotal = iEnd - iBegin;
             Console.WriteLine("Switch took " + iTotal.ToString());


             iBegin = Environment.TickCount;

             for (int x = 0; x < 1000000000; ++x)
             {

                 int i = 1;
                 if (i == 0)
                 {
                 }
                 else if (i == 1)
                 {
                 }
                 else
                 {
                 }
             }

             iEnd = Environment.TickCount;
             iTotal = iEnd - iBegin;
             Console.WriteLine("If-Then took " + iTotal.ToString());

Output on my machine:

Switch took 4828
If-Then took 8016

Has anyone else had any negative results from using switches in C#?

Posted: Mon Jun 04, 2007 1:34 pm C# Performance - Switch vs If-Then

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