1: INTRO
The Fun With the ?? Operator in C#: if { } or ?? – Which is Faster? article by Keith Elder got me thinking about the if statement and the ternary operator.
Is there a real difference or are they both the same?
To answer this question I put together a little project that tests both cases and times them.
2: CODE
using System;
using System.Diagnostics;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
string[] strArray = new string[20000];
Random r = new Random((int)DateTime.Now.Ticks);
for (int i = 0; i < 500; i++)
{
int rnum = r.Next();
if (rnum % 2 == 0)
{
strArray[i] = null;
}
else
{
strArray[i] = rnum.ToString();
}
}
TimeSpan ts1 = TimeSpan.Zero;
TimeSpan ts2 = TimeSpan.Zero;
for (int i = 0; i < strArray.Length; i++)
{
ts2 = ts2.Add(countWithTernary(strArray));
ts1 = ts1.Add(countWithIf(strArray));
}
for (int i = 0; i < strArray.Length; i++)
{
ts1 = ts1.Add(countWithIf(strArray));
ts2 = ts2.Add(countWithTernary(strArray));
}
Console.WriteLine(" if: " + ts1.TotalMilliseconds.ToString());
Console.WriteLine("ternary: " + ts2.TotalMilliseconds.ToString());
Console.ReadLine();
}
private static TimeSpan countWithIf(string[] arr)
{
Stopwatch sw = new Stopwatch();
int len = arr.Length;
int count = 0;
sw.Start();
for (int i = 0; i < len; i++)
{
if (arr[i] == null)
{
count += 1;
}
else
{
count += 2;
}
}
sw.Stop();
return sw.Elapsed;
}
private static TimeSpan countWithTernary(string[] arr)
{
Stopwatch sw = new Stopwatch();
int len = arr.Length;
int count = 0;
sw.Start();
for (int i = 0; i < len; i++)
{
count += arr[i] == null ? 1 : 2;
}
sw.Stop();
return sw.Elapsed;
}
}
}3: RESULTS
The output of the above code suprised me, here are the results:
Here we see that using the if statement is much faster than the ternary operator.
In release the if statement gets faster and the ternary stays about the same.
Surprising to me here was when compiled with x64 the if statement was just as slow (or even slower) than the ternary one.
In release for the x64 they're both almost the same again but the ternary operation is faster than the x86 version.
4: CONCLUSION
In conclusion i think using the if statement would be faster in most cases although in most applications the difference would be unnoticeable.
