C#: generic math functions (Min, Max etc.)

Question

Hello.

I was thinking about writing generic functions for basic Math operations such as Min, Max etc. But i i dont know how to compare two generic types :

 public T Max<T>(T v1, T v2) where T: struct
 {
  return (v1 > v2 ? v1 : v2);
 }

How about that?

Thank you.

Answer 1

You probably want to constrain the generic types to implement IComparable:

public T Max<T>(T v1, T v2) where T: struct, IComparable<T>

and then use the CompareTo method:

{
    return (v1.CompareTo(v2) > 0 ? v1 : v2);
}

Answer 2

From memory, T also needs to be IComparable (add that to the where), and then you use v1.CompareTo(v2) > 0 etc.

Answer 3

If you only want to create comparison functions then you could use the default comparer for the type T. For example:

public static T Max<T>(T x, T y)
{
    return (Comparer<T>.Default.Compare(x, y) > 0) ? x : y;
}

If T implements IComparable<T> then that comparer will be used; if T doesn't implement IComparable<T> but does implement IComparable then that comparer will be used; if T doesn't implement either IComparable<T> or IComparable then a runtime exception will be thrown.

If you want/need to do more than just compare the items then you could have a look at the generic operators implementation in MiscUtil and the related article.