1. Programming in C# Comparison (Sorting)
CSE 494R
(proposed course for 459 Programming in C#)
Prof. Roger Crawfis

2. Comparison
Comparing two instances of a type has many of the same properties and pitfalls as testing for equality.
Equality is generally more fussy.
Only two protocols for a type providing its own comparison:
The IComparable interface
The > and < operators

3. IComparable
The IComparable<T> and IComparable interfaces allow for sorting or ordering of a collection.
They are used in the Array.Sort method.
public interface IComparable <T>{
int CompareTo(T other); // -1 if this < other, 0 if this == other, 1 if this > other }
5.CompareTo(7) => -1
“World”.CompareTo(“Hello”) => 1
32.CompareTo(8*4) => 0

4. IComparable Classes implementing IComparable are
Values types like Int32, Double, DateTime, …
The class Enum as base class of all enumeration types
The class String
Defines a type to be is-a IComparable.

5. The > and < operators
Value types that have a clear context independent concept of less than and greater than should implement the < and > operators.
These are compiled statically into the code, making value types more efficient.

6. Programming in C# Comparison (Sorting)
CSE 494R
(proposed course for 459 Programming in C#)
Prof. Roger Crawfis