if_vs_switch_benchmark.cs

using System;
using System.Security.Cryptography;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

namespace MyBenchmarks
{
    public class IfVsSwitch
    {
        private Random random = new Random(42);

        public IfVsSwitch()
        {
        }

        [Benchmark]
        public string Ifs() {
            var day = random.Next(7);
            if (day == 0) { return "Monday"; }
            else if (day == 1) { return "Tuesday"; }
            else if (day == 2) { return "Wednesday"; }
            else if (day == 3) { return "Thursday"; }
            else if (day == 4) { return "Friday"; }
            else if (day == 5) { return "Saturday"; }
            else if (day == 6) { return "Sunday"; }
            else { return "Unknown"; }
        }

        [Benchmark]
        public string Switch() {
            switch (random.Next(7)) {
                case 0: return "Monday";
                case 1: return "Tuesday";
                case 2: return "Wednesday";
                case 3: return "Thursday";
                case 4: return "Friday";
                case 5: return "Saturday";
                case 6: return "Sunday";
                default: return "Unknown";
                
            }
        }

        [Benchmark]
        public int JustRandom() {
            return random.Next(7);
        }
    }

    public class Program
    {
        public static void Main(string[] args)
        {
            var summary = BenchmarkRunner.Run<IfVsSwitch>();
        }
    }
}

/*
Output from `dotnet run --configuration Release`:

// Benchmark Process 17604 has exited with code 0

Mean = 12.138 ns, StdErr = 0.013 ns (0.11%), N = 14, StdDev = 0.048 ns
Min = 12.066 ns, Q1 = 12.108 ns, Median = 12.123 ns, Q3 = 12.173 ns, Max = 12.212 ns
IQR = 0.065 ns, LowerFence = 12.010 ns, UpperFence = 12.270 ns
ConfidenceInterval = [12.084 ns; 12.192 ns] (CI 99.9%), Margin = 0.054 ns (0.44% of Mean)
Skewness = 0.26, Kurtosis = 1.64, MValue = 2

// ***** BenchmarkRunner: Finish  *****

// * Export *
  BenchmarkDotNet.Artifacts\results\MyBenchmarks.IfVsSwitch-report.csv
  BenchmarkDotNet.Artifacts\results\MyBenchmarks.IfVsSwitch-report-github.md
  BenchmarkDotNet.Artifacts\results\MyBenchmarks.IfVsSwitch-report.html

// * Detailed results *
IfVsSwitch.Ifs: DefaultJob
Runtime = .NET Core 3.1.6 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.31603), X64 RyuJIT; GC = Concurrent Workstation
Mean = 20.247 ns, StdErr = 0.020 ns (0.10%), N = 14, StdDev = 0.076 ns
Min = 20.134 ns, Q1 = 20.197 ns, Median = 20.240 ns, Q3 = 20.298 ns, Max = 20.385 ns
IQR = 0.100 ns, LowerFence = 20.047 ns, UpperFence = 20.448 ns
ConfidenceInterval = [20.161 ns; 20.333 ns] (CI 99.9%), Margin = 0.086 ns (0.43% of Mean)
Skewness = 0.35, Kurtosis = 1.95, MValue = 2
-------------------- Histogram --------------------
[20.093 ns ; 20.426 ns) | @@@@@@@@@@@@@@
---------------------------------------------------

IfVsSwitch.Switch: DefaultJob
Runtime = .NET Core 3.1.6 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.31603), X64 RyuJIT; GC = Concurrent Workstation
Mean = 21.547 ns, StdErr = 0.052 ns (0.24%), N = 15, StdDev = 0.201 ns
Min = 21.302 ns, Q1 = 21.408 ns, Median = 21.471 ns, Q3 = 21.684 ns, Max = 22.001 ns
IQR = 0.276 ns, LowerFence = 20.994 ns, UpperFence = 22.098 ns
ConfidenceInterval = [21.332 ns; 21.761 ns] (CI 99.9%), Margin = 0.214 ns (0.99% of Mean)
Skewness = 0.83, Kurtosis = 2.42, MValue = 2
-------------------- Histogram --------------------
[21.195 ns ; 22.107 ns) | @@@@@@@@@@@@@@@
---------------------------------------------------

IfVsSwitch.JustRandom: DefaultJob
Runtime = .NET Core 3.1.6 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.31603), X64 RyuJIT; GC = Concurrent Workstation
Mean = 12.138 ns, StdErr = 0.013 ns (0.11%), N = 14, StdDev = 0.048 ns
Min = 12.066 ns, Q1 = 12.108 ns, Median = 12.123 ns, Q3 = 12.173 ns, Max = 12.212 ns
IQR = 0.065 ns, LowerFence = 12.010 ns, UpperFence = 12.270 ns
ConfidenceInterval = [12.084 ns; 12.192 ns] (CI 99.9%), Margin = 0.054 ns (0.44% of Mean)
Skewness = 0.26, Kurtosis = 1.64, MValue = 2
-------------------- Histogram --------------------
[12.040 ns ; 12.239 ns) | @@@@@@@@@@@@@@
---------------------------------------------------

// * Summary *

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19041.388 (2004/?/20H1)
Intel Core i7-4770K CPU 3.50GHz (Haswell), 1 CPU, 8 logical and 4 physical cores
.NET Core SDK=3.1.302
  [Host]     : .NET Core 3.1.6 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.31603), X64 RyuJIT
  DefaultJob : .NET Core 3.1.6 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.31603), X64 RyuJIT


|     Method |     Mean |    Error |   StdDev |
|----------- |---------:|---------:|---------:|
|        Ifs | 20.25 ns | 0.086 ns | 0.076 ns |
|     Switch | 21.55 ns | 0.214 ns | 0.201 ns |
| JustRandom | 12.14 ns | 0.054 ns | 0.048 ns |

// * Hints *
Outliers
  IfVsSwitch.Ifs: Default        -> 1 outlier  was  removed (24.35 ns)
  IfVsSwitch.JustRandom: Default -> 1 outlier  was  removed (13.92 ns)

// * Legends *
  Mean   : Arithmetic mean of all measurements
  Error  : Half of 99.9% confidence interval
  StdDev : Standard deviation of all measurements
  1 ns   : 1 Nanosecond (0.000000001 sec)

// ***** BenchmarkRunner: End *****
// ** Remained 0 benchmark(s) to run **
Run time: 00:01:13 (73.12 sec), executed benchmarks: 3

Global total time: 00:01:17 (77.39 sec), executed benchmarks: 3
// * Artifacts cleanup *

*/