Generics SoftUni Team Technical Trainers Software University

2 1.What are Generics? 2.Generic Classes, Generic Interfaces, Generic Methods 3.Type Erasure, Type Parameter Bounds 4.Wildcards Table of Contents

3 sli.do #6442 Questions

4 What are Generics?What are Generics?

5 Generics allow defining parameterized classes What are Generics?

6 Allow processing data of unknown (generic) type What are Generics? (2)

7 List  Generics Example

8 List / List / List Generics Example (2)

9 Provide more readable code Benefits of Generics

10 Generics add type safety Benefits of Generics (2)

11 Generic ClassesGeneric Classes

12 Mostly used as containers Generic Classes

13 Example T is an unknown type, parameter of the class T can be used in any method in the class class GenericList class GenericList { void Add(T element) void Add(T element){…}}

14 Example (2) T is replaced with int during the instantiation T is replaced with string during the instantiation static void Main() { GenericList intList; GenericList intList; GenericList stringList; GenericList stringList;}

15 Conventions

16 Demo

Exercises in Class

18 Generic InterfacesGeneric Interfaces

19 Generic Interfaces add flexibility Generic Interfaces

20 Generic MethodsGeneric Methods

21 Can take generic input and return generic output Generic Methods

22 Generic Method Example static List CreateList (T value, int count) { List genericList = new List (); List genericList = new List (); //add given value count times in the list //add given value count times in the list return genericList return genericList} static void Main() { List strings = CreateList("hello", 5); List strings = CreateList("hello", 5); List numbers = CreateList(10, 3); List numbers = CreateList(10, 3);}

Generic Method – Example (2) static T Min (T first, T second) where T : IComparable where T : IComparable { if(first.CompareTo(second) <=0) if(first.CompareTo(second) <=0) return first; return first; else else return second; return second;} static void Main() { int min = Min (5, 7); // 5 int min = Min (5, 7); // 5 string min = Min (“Annie”, “Ann”) // Ann string min = Min (“Annie”, “Ann”) // Ann} 23

24 Demo

Exercises in Class

26  Generics are parameterized classes  Template classes for processing data of unknown (generic) type  Generic methods can accept generic parameter types  Generic interfaces allow defining flexible contracts Summary

? ? ? ? ? ? ? ? ? OOP Advanced – Generics httpshttps://softuni.bg/courses/oop/

License  This course (slides, examples, demos, videos, homework, etc.) is licensed under the "Creative Commons Attribution- NonCommercial-ShareAlike 4.0 International" licenseCreative Commons Attribution- NonCommercial-ShareAlike 4.0 International 28  Attribution: this work may contain portions from  "Fundamentals of Computer Programming with C#" book by Svetlin Nakov & Co. under CC-BY-SA licenseFundamentals of Computer Programming with C#CC-BY-SA  "OOP" course by Telerik Academy under CC-BY-NC-SA licenseOOPCC-BY-NC-SA

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