Ch11 - Try it out Ex5

stuartho · December 20th, 2011, 02:14 PM

Would like to make sure I understand the concept behind the line of code in the class PersonComparerName:

Code:

public static IComparer Default = new PersonComparerName();

As I understand it - it is for "ease of use" in that it allows a short cut to instantiating an instance of IComparer (based on an instance of PersonComparerName via polymorphism) in this case for use in the line in program.cs:

Code:

list.Sort(PersonComparerName.Default);

One could also eliminate that line (in PersonComparerName above) and then either do something in program.cs like:

Code:

IComparer PersonCompareNameIComparer = new PersonComparerName();
list.Sort(PersonCompareNameIComparer);

or even :

Code:

list.Sort(new PersonComparerName());

(they both seem to work for me anyway).

Thanks for any additional clarification or insights on this.

stuartho

ChristianNagel · December 29th, 2011, 05:51 PM

if you use a "new PersonComparerName()" every time you're going to sort it that way you end up with multiple instances of PersonComparerName. If you are using "PersonComparerName.Default", only one instance of PersonComparerName is used.