General Performance Tip: Constant vs Variable

Updated March 2024

When including numerical or string values in code that remain static, it is advisable to transform them into constants.

This is an example of exposing the value of π through a read-only field.

public class CircleCalculator
{
    private readnly double _pi = 3.1415926535897932384626433832;
}

This is the same example using a constant.

public class CircleCalculator
{
      public const double PI = 3.1415926535897932384626433832;
}

Benchmark Results

This benchmark illustrates that employing a constant is 3.2 times faster than utilizing a variable!

My recommendation is to use constants where appropriate. This shows the intent of the variable.
This is related to violation CA1802 and this is how I have it setup in my EditorConfig: dotnet_diagnostic.CA1802.severity = warning

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