C# reference

Concepts

The C# concept exercises are based on concepts. The list below contains the concepts that have been identified by the track maintainers for the C# language.

(Please do not modify this document. it is automatically generated. All text except the concept learning objectives is sourced from exercises.json which should be updated manually when a concept is added, an "new exercise" issue is raised or the exercise is completed and merged into master. Learning objectives are scraped from the concept definition text in each exercise's design.md document and should be modified there as required.)

This report is updated automatically when any design.md document is modified or csharp/reference/README.md is edited.

Introductory Concepts

• arrays (bird-watcher) - Design, Background
• assignment (cars-assemble) - Design
• base-class-library (international-calling-connoisseur) - Design
• basics (lucians-luscious-lasagna) - Design
• bit-manipulation (attack-of-the-trolls) - Design
• booleans (annalyns-infiltration) - Design, Background
• booleans (annalyns-infiltration) - Design
• casting (secure-munchester-united) - Design
• chars (squeaky-clean) - Design, Background
• classes (elons-toys) - Design, Background
• collections (tracks-on-tracks-on-tracks) - Design
• constants (authentication-system) - Design
• constructors (need-for-speed) - Design
• cross-platform (beauty-salon-goes-global) - Design
• datetimes (booking-up-for-beauty) - Design
• defensive-copying (authentication-system) - Design
• dictionaries (international-calling-connoisseur) - Design, Background
• do-while-loops (interest-is-interesting) - Design
• enums (logs-logs-logs) - Design
• equality (faceid-2) - Design, Background
• exception-filtering (instruments-of-texas) - Design
• exceptions (calculator-conundrum) - Design
• explicit-interfaces (remote-control-competition) - Design
• expression-bodied-members (the-weather-in-deather) - Design
• flag-enums (attack-of-the-trolls) - Design
• floating-point-numbers (interest-is-interesting) - Design
• for-loops (bird-watcher) - Design, Background
• foreach-loops (bird-watcher) - Design, Background
• generic-types (tracks-on-tracks-on-tracks) - Design
• if-statements (cars-assemble) - Design, Background
• implicit-casting (secure-munchester-united) - Design
• imports (red-vs-blue-darwin-style) - Design
• inheritance (wizards-and-warriors) - Design, Background
• integral-numbers (hyper-optimized-telemetry) - Design
• interfaces (remote-control-competition) - Design, Background
• interpolation (high-school-sweethearts) - Design
• lists (tracks-on-tracks-on-tracks) - Design, Background
• marker-interfaces (faceid-2) - Design
• math-operators (cars-assemble) - Design
• method-overloading (wizards-and-warriors-2) - Design
• named-arguments (wizards-and-warriors-2) - Design
• namespaces (red-vs-blue-darwin-style) - Design
• nested-types (remote-control-cleanup) - Design
• null-coalescing (tim-from-marketing) - Design
• null-conditional (tim-from-marketing) - Design
• null-forgiving (tim-from-marketing) - Design
• nullability (tim-from-marketing) - Design
• nullable-values (tim-from-marketing) - Design
• numbers (cars-assemble) - Design
• numbers (cars-assemble) - Design
• object-initializers (developer-privileges) - Design
• operator-overloading (hyperia-forex) - Design
• optional-arguments (building-telemetry) - Design, Background
• optional-parameters (wizards-and-warriors-2) - Design
• ordering (remote-control-competition) - Design
• out-parameters (building-telemetry) - Design
• overflow (hyperinflation-hits-hyperia) - Design
• parameters (building-telemetry) - Design
• properties (weighing-machine) - Design
• randomness (roll-the-die) - Design
• readonly-collections (authentication-system) - Design
• regular-expressions (parsing-log-files) - Design
• resource-cleanup (object-relational-mapping) - Design
• resource-lifetime (orm-in-one-go) - Design
• sets (faceid-2) - Design, Background
• string-builder (squeaky-clean) - Design
• string-formatting (high-school-sweethearts) - Design
• strings (log-levels) - Design, Background
• structs (land-grab-in-space) - Design
• switch-expressions (the-weather-in-deather) - Design
• switch-statements (football-match-reports) - Design
• ternary-operators (the-weather-in-deather) - Design, Background
• throw-expressions (the-weather-in-deather) - Design
• time (beauty-salon-goes-global) - Design
• timezone (beauty-salon-goes-global) - Design
• tuples (phone-number-analysis) - Design, Background
• unsigned-integers (hyper-optimized-telemetry) - Design
• user-defined-exceptions (instruments-of-texas) - Design
• verbatim-strings (high-school-sweethearts) - Design
• while-loops (interest-is-interesting) - Design

Essential Concepts

• anonymous-types (anonymous-types)
• async (async)
• attributes-advanced (attributes-advanced) - Issue
• collections-combining (linq)
• collections-filtering (linq)
• collections-mapping (linq)
• collections-ordering (linq)
• collections-reducing (linq)
• contravariance (contravariance)
• covariance (covariance)
• delegates (delegates)
• enumerables (enumerables)
• events (events)
• extension-methods (extension-methods) - Issue
• generics-advanced (generics-advanced)
• higher-order-functions (higher-order-functions) - Background
• indexers (indexers)
• lambdas (lambdas) - Background
• linq (linq) - Background
• linq-advanced (linq-advanced)
• linq-query-syntax (linq-query-syntax)
• linq-select-many (linq-select-many)
• locks (locks)
• pattern-matching-tuples (pattern-matching-tuples) - Issue
• pattern-matching-types (pattern-matching-types) - Issue
• recursion (recursion) - Background
• reflection (reflection)
• serialization (serialization)
• statics (statics)
• streams (streams)
• tasks (tasks)
• thread-safety (thread-safety)
• yield (yield)

Advanced Concepts

• aysnc-iterators (aysnc-iterators)
• boxing (boxing)
• by-ref (by-ref)
• destructors (destructors)
• dispose-pattern (dispose-pattern)
• dynamic (dynamic)
• immutability (immutability) - Background
• immutable-collections (immutable-collections)
• lazy (lazy)
• local-functions (local-functions) - Background
• memory-allocation (memory-allocation) - Issue
• multi-dimensional-array (multi-dimensional-array)
• pointsers (pointers) - Issue
• queues (queues) - Background
• ranges (ranges) - Background
• ref-local (ref-local)
• resource-pooling (resource-pooling) - Issue
• slicing (slicing)
• stacks (stacks) - Background
• time-zones (time-zones)
• unsafe-code (unsafe-code)

Unallocated Concepts

• formatting-types (unallocated-concepts)

Learning Objectives

Concept	Learning Objectives
arrays	know of the existence of the Array type know how to define an array know how to access elements in an array by index know how to update an element in an array by index know how to iterate over elements in an array know of some basic functions (like finding the index of an element in an array).
assignment	know the syntax and behavior of assignment in OO languages
base-class-library	know of the existence and role of the base class library
basics	know what a variable is know how to define a variable know how to update a variable know how to use type inference for variables know how to define a method know how to return a value from a method know how to call a method know that methods must be defined in classes know about the public access modifier know about the static modifier know how to define an integer know how to use mathematical operators on integers know how to define single- and multiline comments. The following sub-concepts are included type-inference, return-values, mutation, functions, comments, scoping, variables
booleans	know of the existence of the bool type and its two values know about boolean operators and how to build logical expressions with them know of the boolean operator precedence rules.
booleans	know of the existence of the bool type and its two values know about boolean operators and how to build logical expressions with them know of the boolean operator precedence rules.
casting	know what explicit and implicit casts are know how to do an explicit cast know how to use is and as to convert between types.
chars	know of the existence of the char type know that a char represents know how to define a char know how to access a char in a string by index know of some basic char methods (like converting to uppercase).
classes	know what classes are know what encapsulation is know what fields are know how to create an object know how to update state through methods know about the void type.
collections	know the role of collections in OO languages
constants	know how to define const values know how to define readonly modifier know when to use const or readonly.
constructors	know what constructors are know how to define parameterless constructors know how to define parameterized constructors know how to use constructor overloading know how to define private constructors.
cross-platform	know how to have different code paths (selected at run-time) for Linux, Windows and Mac
datetimes	know how to create a DateTime instance know how to get the current date know of the individual, date-related properties know how to access the current date know how to compare dates know how to convert a string to a DateTime and vice versa know of the existence of the DateTime type know of the individual, time-related properties.
defensive-copying	know how and when to use defensive copying
dictionaries	know of the existence of the Dictionary<TKey, TElement> type know how to define a dictionary know how to add and updated elements in a dictionary know how to access elements in a dictionary by key know how to iterate over elements in a dictionary know some basic dictionary functions.
do-while-loops	know the syntax of do loop know when to use a do loop
enums	know of the existence of the enum keyword know how to define enum members know how to assign values to enum members know how to get an enum's numeric value know how to convert an enum to a string.
equality	know how to check for equality and inequality know how reference equality differs from structural equality know that equality works by default for value and reference types know how to customize equality checks using Equals and GetHashCode() know of the IEquatable<T> and IEqualityComparer<T> interfaces and how to implement them.
exception-filtering	know how to use exception filtering.
exceptions	know what exceptions are know when an exception should be thrown know how to throw (and rethrow) an exception know how to catch an exception know the most important built-in exceptions (ArgumentException, InvalidOperationException).
explicit-interfaces	know how an explicit interface is declared know how use an explicit interface know why explicit interfaces are useful
expression-bodied-members	know the difference between statements and expressions know how to define expression bodied members.
flag-enums	know how to define a "flags" enum know how to add, remove or check for flags know how to change the underlying type of an enum.
floating-point-numbers	know of the existing of the three floating point types: double, float and decimal. know when to use which floating point type.
for-loops	know how to use a for loop to do iteration.
foreach-loops	know how to iterate over a collection.
generic-types	know what generic types are.
if-statements	know how to conditionally execute code using an if statement.
implicit-casting	know about implicit type conversion
imports	know how to import namespaces with the using directive
inheritance	know what inheritance is know how to inherit from a class know that all types inherit from object know what abstract and sealed classes are know what abstract and virtual methods are know how to override methods know about the protected visibility modifier.
integral-numbers	know of the difference between signed and unsigned integral types know of the existence of the integral types: sbyte, byte, short, ushort, int, uint, long and ulong know when to use which integral type.
interfaces	know what interfaces are know how to use interfaces know how to define an interface know how to implement an interface know how to explicitly implement an interface.
interpolation	know how the syntax of interpolated strings know when to use string interpolation
lists	know of the existence of the List<T> type know how a list is different from an array know how to define a list know how to add and remove elements from a list know how to access elements in a list by their index know how to iterate over elements in a list know some basic list functions (like finding the index of an element in a list).
marker-interfaces	know what a marker interface is know of some common marker interfaces
math-operators	know the math operators know about precedence know the role of parentheses
method-overloading	know what method overloading is know how to define overloaded methods know the limitations of method overloading
named-arguments	know how to use named arguments
namespaces	know what namespaces are know how to import namespaces.
nested-types	know syntax for nested classes know when to use nested classes familiarity with other nested types such as structs and enums
null-coalescing	know the syntax and behavior of the null-coalescing operator (??)
null-conditional	know the syntax and behavior of the null-conditional operator (?.)
null-forgiving	know the syntax and behavior of the null-forgiving operator (!.) know to use the operator with discretion
nullability	know of the existence of the null literal know what a NullReferenceException is and when it is thrown know how to compare a value to null know the difference between value and reference types regarding nullability know how to define nullable reference and value types know about the null-related operators know about basic null checking by the compiler.
nullable-values	know about nullable primitives know about nullable structs
numbers	know of the existence of the two most commonly used number types, int and double understand that the former represents whole numbers, and the latter floating-point numbers know of basic operators such as multiplication, comparison and equality know how to convert from one numeric type to another know what implicit and explicit conversions are.
numbers	know of the existence of the two most commonly used number types, int and double understand that the former represents whole numbers, and the latter floating-point numbers know of basic operators such as multiplication, comparison and equality know how to convert from one numeric type to another know what implicit and explicit conversions are.
object-initializers	Know how to initialize objects using object initialization syntax. Know how to initialize lists and dictionaries. Understand the relative advantages of constructors and initializers.
operator-overloading	know when to how and why to overload operators for your own classes understand the syntax of equality, comparison and arithmetic operators know the syntax of user defined type conversion know which operators cannot be overloaded
optional-arguments	know the syntax and behavior or optional arguments
optional-parameters	know how to define optional parameters
ordering	know how to implement the IComparable<T> interface and what its effect is on the behavior of collections.
out-parameters	know the syntax of out parameters know the role of out parameters
overflow	explain integral number overflows explain floating-point number overflows know how to use checked and unchecked to deal with overflows.
parameters	know the difference between value and reference type parameters know how to pass value types by reference using the ref and out modifiers.
properties	know what properties are and how they relate to fields and methods know what backing-field properties are know what auto-implemented properties are know what calculated properties are know how to use property accessors to customize visibility know how to define the different types of properties.
randomness	know how to implement randomness with System.Random in C# know that no seed is required know that both integers and real numbers can be generated know that once generated random numbers can be easily used for many purposes (including non-numeric ones)
readonly-collections	know how to make a collection read-only understand the difference between the role of the readonly modifier and the use of readonly collections
regular-expressions	Know how to use regular expressions with Regex in C# Know how to identify the presence of a pattern in a string Know how to "capture" and replace text identified by patterns Know how to use the Options property of Regex Know that search performance can be enhanced by compiling Regex (discussion only)
resource-cleanup	Know how to clean up resources with IDisposable in C# and .NET. Understand the difference between managed and unmanaged resources and the role of IDisposable.
resource-lifetime	Know how to control a resource's lifetime with the using statement in C#
sets	Know how to use hash sets HashSet<T> as provided by the .NET BCL. Understand the relationship with Object.GetHashCode() and the performance characteristics of hash sets.
string-builder	know how to use a StringBuilder know that it is more performant than simple concatenation
string-formatting	know how to use the ToString() method to convert any object to a string know how to use string interpolation on values of any type know how to use default format strings to convert to standard output formats know how to use custom format strings to convert to custom output formats know that string.Format underlies string interpolation know that string interpolation can interpolate any expression.
strings	know of the existence of the string type know of some basic functions (like looking up a character at a position, or slicing the string) know how to do basic string formatting.
structs	know xx what structs are know how to define a struct know how to add members to structs know the differences between structs and classes.
switch-expressions	know how to pattern match on values know how to use when guards
switch-statements	Know how to use switch statements
ternary-operators	know how and when to use the ternary operator.
throw-expressions	know how to use a throw expression.
time	Know how to use DateTime when time-of-day is important. Understand the difference between local time and Universal Coordinated Time). Understand the role of CultureInfo in parsing times. Understand arithmetic with DateTimes.
timezone	Know about time zones and their ids. Be familiar with cross-platform issues. Know how to convert dates and times between time zones. Know how to detect daylight saving time.
tuples	know what a tuple is know how to define a tuple know how to name tuple fields know that tuples have structural equality know how to deconstruct tuples know that tuples are mutable.
unsigned-integers	know the characteristics of unsigned integers
user-defined-exceptions	know how to define a user-defined exception.
verbatim-strings	the syntax of verbatim strings
while-loops	know how to write a while loop.