INFO5101 - Exam

Question 1

What are the data structures which represent the logic of the lambda expressions and can be examined by other code called?

Answer 1

Expression Trees

Question 2

Lambda expressions can be seen as an evolution of what?

Answer 2

Anonymous Methods

Question 3

What is the maximum number of parameters a Func<> declaration can include?

Answer 3

16

Question 4

What is an example of a Func delegate signature that takes 2 arguments?

Answer 4

TResult Func<T1, T2, TResult>(T1 arg1, T2 arg2)

Question 5

What is the last type parameter in a Func delegate?

Answer 5

The return type

Question 6

What is the return type of an Action<…> delegate?

Answer 6

Void

Question 7

What is the lambda declaration operator?

Answer 7

=>

Question 8

What operator means “goes to”

Answer 8

Lambda Declaration Operator (=>)

Question 9

What is on the left hand side of the lambda declaration operator?

Answer 9

Parameter List

Question 10

What is on the right hand side of the lambda declaration operator?

Answer 10

Method Body

Question 11

What is an implicitly typed lambda expression?

Answer 11

Comma-separated list of names without types for the parameter list

Question 12

What is the rule with implicitly typed lambda expressions?

Answer 12

All parameters must be implicit or explicit. Cannot mix and match

Question 13

When MUST you use explicit typing with lambda expressions?

Answer 13

If any parameters are “out” or “ref”

Question 14

Which expressions are created first in expression trees?

Answer 14

Leaf expressions

Question 15

What is meant by “expressions are immutable”?

Answer 15

Once created it cannot change

Question 16

What do you get when you combine lambda expressions, expression trees, and extension methods?

Answer 16

Language side of LINQ

Question 17

Extension methods can only be declared in what type of class?

Answer 17

Static

Question 18

Can an extension class be generic?

Answer 18

No

Question 19

What is the minimum number of parameters for an extension method?

Answer 19

1

Question 20

What must the first parameter of an extension method be prefixed with?

Answer 20

this

Question 21

What 3 things can the first parameter of an extension method NOT be?

Answer 21

1. out
2. ref
3. pointer type

Question 22

What is it called when the compiler is trying to decide which method to use when an extension method is called?

Answer 22

Compiler Resolution

Question 23

What happens if there is an instance method that matches an extension method’s expression type?

Answer 23

The instance method is used

Question 24

What are the 2 classes that contain most of the extension methods for LINQ providers?

Answer 24

1. Enumerable
2. Queryable

Question 25

What namespace holds the Enumerable and Queryable classes?

Answer 25

System.Linq

Question 26

What is it called when a method yields data in a just-in-time fashion?

Answer 26

Deferred Execution

Question 27

What are 2 methods that use deferred execution?

Answer 27

1. Range 2. Reverse

Question 28

What type does the Where() method return?

Answer 28

IEnumerable< T >

Question 29

Three benefits of extension methods are improved readability, calling as if they were instance methods, and what?

Answer 29

Easily chained together

Question 30

What is the main difference between using OrderBy() and .Sort()?

Answer 30

OrderBy returns a new list, Sort changes the original list

Question 31

What is meant by LINQ operators are side-effect-free?

Answer 31

They don't change their input or the environment

Question 32

Where does the side-effect-free approach come from?

Answer 32

Functional Programming

Question 33

LINQ

Answer 33

Language-Integrated Query

Question 34

How does a query expression start?

Answer 34

Stating the source of data

Question 35

What else is the select clause known as?

Answer 35

Projection

Question 36

The first compiler phase of translating query expressions is a ____________ step

Answer 36

Preprocessor

Question 37

Query expressions are first compiled into what?

Answer 37

Dot Notation

Question 38

Why are query expressions backwards compared to SQL queries?

Answer 38

Processed in the order it is written

Question 39

Can all query expressions be written in dot notation?

Answer 39

Yes

Question 40

Can all dot notation queries be written as a query expression?

Answer 40

No

Question 41

What happens when an async method is awaiting a process?

Answer 41

Control returns to caller of method

Question 42

What is a continuation?

Answer 42

Callback to be executed after asynchronous operation has completed

Question 43

What are the 3 possible return types of an async method?

Answer 43

1. Void 2. Task 3. Task< TResult>