Clamp

/// <summary>
///   Limit a value to a certain range. When the value is smaller/bigger than the range, snap it to the range border.
/// </summary>
/// <typeparam name = "T">The type of the value to limit.</typeparam>
/// <param name = "source">The source for this extension method.</param>
/// <param name = "start">The start of the interval, included in the interval.</param>
/// <param name = "end">The end of the interval, included in the interval.</param>
public static T Clamp<T>( this T source, T start, T end )
	where T : IComparable
{
	bool isReversed = start.CompareTo( end ) > 0;
	T smallest = isReversed ? end : start;
	T biggest = isReversed ? start : end;

	return source.CompareTo( smallest ) < 0
		? smallest
		: source.CompareTo( biggest ) > 0
			? biggest
			: source;
}

int 50;
int clamped = 50.Clamp( 0, 20 ); // clamped == 20