You could write an extension method:
public static T Clamp<T>(this T val, T min, T max) where T : IComparable<T>
{
if (val.CompareTo(min) < 0) return min;
else if(val.CompareTo(max) > 0) return max;
else return val;
}
Extension methods go in static classes – since this is quite a low-level function, it should probably go in some core namespace in your project. You can then use the method in any code file that contains a using directive for the namespace e.g.
using Core.ExtensionMethods
int i = 4.Clamp(1, 3);
.NET Core 2.0
Starting with .NET Core 2.0 System.Math
now has a Clamp
method that can be used instead:
using System;
int i = Math.Clamp(4, 1, 3);