self study

Question 1

What does Built-In mean?

Answer 1

Refers to functionalities, types, or features that are an integral part of the Swift language itself.

These are provided directly by the Swift standard library or are part of the Swift compiler, and they are readily available without the need for additional imports or external dependencies.

Question 2

Functions and methods with no return type have an implicit return type of ______

Answer 2

Void

Question 3

A struct is a ____ type

Answer 3

Value

Question 4

A class is a ____ type

Answer 4

Reference

Question 5

The language used by Apple before Swift:

Answer 5

Objective-C

Question 6

Are variables always initialized before use?

Answer 6

Yes

Question 7

Fundamental Data Types:

Answer 7

Integers, Double, Bool, String

Question 8

Collection Types:

Answer 8

Array, Set, Dictionary

Question 9

A tuple is an ____ type

Answer 9

Advanced

Question 10

The language helps you to be clear about the types of values your code can work with.

For example, if your code requires a String, type safety prevents you from passing an Int by mistake

Answer 10

Type-Safe

Question 11

Swift performs type-safe checks when ____ the code

Answer 11

Compiling

Question 12

Must be declared before they’re used

Answer 12

Constants and Variables

Question 13

Enables a compiler to deduce the type of a particular expression automatically when it compiles your code, simply by examining the values you provide

Answer 13

Type Inference

Question 14

Write a ___________ by placing a colon after the constant of variable name, followed by a space, followed by the name of the type to use

Answer 14

Type Annotation

Question 15

In the following code, the “String” word can be defined as:

var myWord: String

Answer 15

Type Annotation

Question 16

It’s a value that appears directly in your source code. The number 42 is a ______

E.g let meaningOfLife = 42

Answer 16

Literal Value

Question 17

If you need to give a constant or variable the same name as the reserved Swift keyword, surround the keyword with ____

Answer 17

backticks (`)

Question 18

Include the name of a constant or variable as a placeholder in a longer string

Answer 18

String interpolation

Question 19

How do you represent, single, multiple lines comments?

Answer 19

// Single line


/* Multiple lines */


/* This is the start of the first multiline comment.
 /* This is the second, nested multiline comment. */
This is the end of the first multiline comment. */

Question 20

Whole numbers with no fractional component, Signed positive, zero, negative.

Answer 20

Integers

Question 21

Represents a 64-bit floating-point number and it is preferred and inferred when you don’t specify a type

Answer 21

Double

Question 22

Values are referred to as logical because they can only be true or false

Answer 22

Booleans (Bool)

Question 23

The values within a ____ can be of any type and don’t have to be of the same type as each other

Answer 23

tuple

Question 24

You can ____ a tuples contents into separate constants or variables

Answer 24

decompose

Question 25

This is an example of a:

let http404Error = (404, “Not Found”)

Answer 25

Tuple

Question 26

Define an alternative name for an existing type and use the keyword ____

Answer 26

Type Aliases

typealias

Question 27

You use ____ in the situation where a value may be absent, it represents two possibilities:
Either there is a value of a specified type, and you can unwrap the ____ to access that value, or there isn’t a value at all

Answer 27

Optionals

Question 28

If you define an optional variable without providing a default value, the variable is automatically set to ____

Answer 28

nil

Question 29

Trailing question mark

Answer 29

?

Question 30

You must ____ the value of an Optional instance before you can use it in many contexts

Answer 30

unwrap

Question 31

Mention the ways to safely unwrap optional values

Answer 31

*Optional Binding
*Optional Chaining
*Nil-Coalescing Operator
*Force unwrapping / Unconditional Unwrapping

Question 32

This is useful when an optional’s value is confirmed to exist immediately after the optional is first defined and can definitely be assumed to exist at every point thereafter.

Answer 32

Implicitly Unwrapped Optional

Question 33

To conditionally ____ the wrapped value of an Optional instance to a new variable, use one of the optional ____ control sources

Answer 33

bind / binding

Question 34

This safely unwrap optional value, includes:

if let, guard let, and switch

Answer 34

Optional binding

Question 35

It’s a process for querying and calling properties, methods, and subscripts on an optional that might currently be nil

Answer 35

Optional Chaining

Question 36

Multiple queries can be chained together, and the entire chain ____ gracefully if any link in the chain is nil

Answer 36

falls

Question 37

Postfix optional chaining operator

Answer 37

(postfix ?)

Question 38

Use the ____ to supply a default value in case the Optional instance is ____

Answer 38

nil-coalescing operator / nil

Question 39

nil-coalescing operator

Answer 39

??

Question 40

When you are certain that an instance Optional contains a value, you can unconditionally unwrap the value by using the ____ operator

Answer 40

force unwrap

Question 41

Forced unwrap operator

Answer 41

(postfix !)

Question 42

Unconditionally unwrapping a nil instance with ! Triggers a ____

Answer 42

runtime error

Question 43

This is an example of a ____

let assumedString: String! = “Hello”

Answer 43

Implicitly Unwrapped Optional

Question 44

Assertions and Preconditions are checks that happen ____, you use them to make sure an essential condition is satisfied before executing any further code.

Answer 44

a runtime

Question 45

If the boolean condition in the assertion or precondition is ____, code execution continues as usual, if it’s ____, the current state of the program is invalid, code execution ends and your app is terminated.

Answer 45

true
false

Question 46

____ help you find mistakes and incorrect assumption during ____, and ____ help detect issues in ____

Answer 46

Assertions
development
preconditions
production

Question 47

Which is the difference between assertions and preconditions ?

It’s when they are ____

Assertions are checked only in ____ builds.

Preconditions are checked in both ____ and ____ builds.

Answer 47

Checked
debug
debug
production

Question 48

in production builds, the condition inside an assertion is evaluated.

Answer 48

No

Question 49

You write an assertion by calling the ____ function


Answer 49

assert(::file:line:)

Question 50

If the code already checks for the condition, you use ____ function to indicate that an assertion has failed

Answer 50

assertionFailure(::file:line:)

Question 51

You write precondition by calling ____ function

Answer 51

precondition(::file:line:)

Question 52

You can also call the ____ function to indicate that a failure has occurred

Answer 52

preconditionFailure(::file:line:)

Question 53

Defines a blueprint of methods, properties, and any other requirements that suit a particular task or piece of functionality

Answer 53

Protocol

Question 54

A protocol defines a ____ of ____ and ____

Answer 54

blueprint
methods
properties

Question 55

A protocol can be adopted by a ___, ___ and ___

Answer 55

class
struct
enum

Question 56

Any time that satisfies the requirements of a protocol is said to ____ to that protocol

Answer 56

conform

Question 57

You can ____ a protocol

Answer 57

extend

Question 58

Can multiple protocols be listed?

Answer 58

Yes, separated by commas

Question 59

If a class has a superclass, list a superclass ____ the protocols

Answer 59

before

Question 60

Why do protocols begin with a capital letter?

Answer 60

Because protocols are types

Question 61

Protocol doesn’t specify whether the property should be stored or computed, it only specifies whether each property must be ____, or ____and ____.

Answer 61

gettable
gettable
settable

Question 62

what is it
var mustBeSettable: Int { get set }

Answer 62

A property declared in a protocol

Question 63

Default values, however, can’t be specified for method parameters within a protocol’s definition

True or False?

Answer 63

True

Question 64

Protocols can require specific initializers to be implemented by conforming types.

protocol SomeProtocol {
init(someParameter: Int)
}

True or False?

Answer 64

True,
You write these initializers as part of the protocol’s definition in exactly the same way as for normal initializers, but without curly braces or an initializer body

Question 65

Mutating keyword only applies to ____

Answer 65

structs

Question 66

To force a protocol to be limited to class types only, you can add the ____ protocol to its inheritance list

Answer 66

AnyObject

protocol SecretClassFeature:AnyObject {

func secretClassFeature () 

}

Question 67

What does the delegation design pattern do?

Answer 67

Enables a class or structure to hand off (or delegate) some of its responsibilities to an instance of another type

Question 68

delegates are declared as ____ references

Answer 68

weak

Question 69

A protocol can be used as the type to be stored in a collection such as an array or a dictionary?

True or False

Answer 69

True

Question 70

A protocol can ____ one or more protocols and can add further requirements on top of the requirements it inherits.

Answer 70

inherit

protocol InheritingProtocol: SomeProtocol, AnotherProtocol {

}

Question 71

what is protocol composition?

Answer 71

You can combine multiple protocols into a single requirement

You can also create a typealias using protocol composition



typealias RobotQ = Bipedal & PetrolPowered

Question 72

What are Optional Protocol Requirements?

Which is the optional modifier?

Answer 72

You can define optional requirements of protocols. These requirements don’t have to be implemented by types that conform to the protocol.

Those are prefixed with the optional modifier, Both the protocol and the optional requirement must be marked with the @objc attribute,

Question 73

What are extensions?

Answer 73

Allow you to add brand-new functionality to existing classes, structures, and protocols. You can use extensions to add computed properties, methods, or initializers, or make something conform to a protocol.

Question 74

Extensions can add methods and computed properties, but not ____ properties

Answer 74

stored

Question 75

Assignment operator

Answer 75

=

Question 76

Equal operator

Answer 76

==
Returns a boolean

Question 77

+ - * /

Answer 77

Arithmetic Operators

Question 78

%

Answer 78

Reminder or modulo operator

Question 79

+=

Answer 79

Compound operator

Question 80

1…5

Answer 80

Closed Range operator

Question 81

a..<b

Answer 81

Half Open Range Operator

Question 82

2… or …2

Answer 82

One-Sided Ranges

Question 83

NOT !a
AND ( && )
OR (a | | b )

Answer 83

Logical Operators

Question 84

Name the logical operators

Answer 84

NOT !a
AND ( && )
OR (a | | b )

Question 85

____ operator appears immediately before their target

Answer 85

Unary prefix
!c

Question 86

____ operator appears immediately after their target

Answer 86

Unary postfix
c!

Question 87

____ operators operate on two targets, Example: 2 + 3, and are ____ because they appear in between two targets

Answer 87

Binary Operators
infix

Question 88

____ operators operate on three targets, ternary conditional operator (a ? b : c)

Answer 88

Ternary

Question 89

String is a ____ type

Answer 89

Value
it means that the value is copied

Question 90

What is a String?

Answer 90

A series of characters

Question 91

From which class comes String?

Answer 91

Foundation’s NSString class

Question 92

A ____ is a sequence of characters surrounded by double quotation marks (“)

Answer 92

A string literal

Question 93

You can append a character value to a String variable with the String type’s ____ method

Answer 93

append()

Question 94

Can you append a String or Character to an existing Character variable?

Answer 94

No, because a Character value must contain a single character only

Question 95

____ is an international standard for encoding, representing, and processing text in different writing systems

Answer 95

Unicode

Question 96

To retrieve a count of the character values in a string, use the ____ property of the string

Answer 96

count()

var word = “cafe”
 word.count()

Question 97

____ property to access the position of the first character of a String

Answer 97

startIndex

Question 98

____ property is the position after the last character in a String

Answer 98

endIndex

Question 99

You can access the indices before and after a given index using the ____ and ____ methods of String

Answer 99

index(before:)
index(after:)

Question 100

To access an index farther away from the given index, you can use ____ method

Answer 100

index(_:offsetBy:)

Question 101

To insert a single character into a string at a specified index, use the ____ method

Answer 101

insert(_:at:)

Question 102

To insert the contents of another string at a specified index, use the ____ method

Answer 102

insert(contentsOf:at:)

Question 103

To remove a single character, from a string at a specified index, use ____ method

Answer 103

remove(at:)

Question 104

To remove a substring at a specified range, use the ____ method

Answer 104

removeSubrange(_:)

Question 105

When you get a substring from a string, the result is an instance of ____ not another string

Answer 105

substring

Question 106

Two string values (or two Character values) are considered equal if their extended grapheme clusters are canonically equivalent

True or False?

Answer 106

True

Question 107

To check whether a string has a particular string prefix or suffix, call the string’s ____ and ____ methods, both take a String and return a ____ value

Answer 107

hasPrefix(:)
hasSuffix(:)
Boolean

Question 108

Array, set and dictionaries are ____ when assigned to a variable, this means that can change or mutate the collection after it’s created by adding, removing or changing items in the collection, but are ____ when assigned to a constant, and it’s size contents ____ be changed

Answer 108

mutable
immutable
can’t

Question 109

Which Collection Type is it?
Ordered collection of values

Answer 109

Array

Question 110

Which Collection Type is it?
Always zero-indexed

Answer 110

Array

Question 111

If you try to access or modify a value for an index that’s outside of an array’s existing bounds, you will trigger a ____.

Answer 111

runtime error

Question 112

What does the following code do?
var emptyArray: [Int] = []

Answer 112

It creates an empty array

Question 113

Write the code to create an empty array:

Answer 113

var emptyArray: [Int] = []

Question 114

Explain the following code:
var shoppingList: [String] = [“Eggs”, “Milk”]

This is an array ____

Answer 114

literal

Question 115

Why shoppingList doesn’t have a type?

var shoppingList = [“Eggs”, “Milk”]

Answer 115

Type inferences don’t need to write the type of the array

Question 116

Property to verify if a an arrary is empty?

Answer 116

.isEmpty

if shoppingList.isEmpty {
 print(“The shopping list is empty.”
} else {
 print(“The shopping list isn’t empty.”
}

Question 117

Method to add a new item at the end of the array

Answer 117

append(_:)method

You can add a new item to the end of an array by calling the array’sappend(_:)method
shoppingList.append(“Flour”)

Question 118

Retrieve a value from the array by usingsubscript syntax, passing the ____ of the value

Answer 118

index

var firstItem = shoppingList[0]

Question 119

To insert an item into the array at a specified index, call the array’s____ method:

Answer 119

insert(_:at:)

shoppingList.insert(“Maple Syrup”, at: 0)


Question 120

You remove an item from the array with the____method


Answer 120

remove(at:)

let mapleSyrup = shoppingList.remove(at: 0)

Question 121

If you want to remove the final item from an array, use the____method

Answer 121

removeLast()

let apples = shoppingList.removeLast()

Question 122

If you need the integer index of each item as well as its value, use the____ method to iterate over the array instead. For each item in the array, the____method returns a tuple composed of an integer and the item.

Answer 122

enumerated()

Question 123

Explain the following code:

for (index, value) in shoppingList.enumerated() {
 print(“Item (index + 1): (value)”)
 }
// Item 1: Six eggs
// Item 2: Milk
// Item 3: Flour
// Item 4: Baking Powder
// Item 5: Bananas


Question 124

Unordered collection of unique values

Answer 124

Set

Question 125

var letters = Set<Character>()</Character>

Answer 125

Creating an empty set

Question 126

Coding:
Create an empty set

Answer 126

var letters = Set<Character>()</Character>

Question 127

Design Principles (6)

Answer 127

Aesthetic Integrity
Consistency
Direct Manipulation
Feedback
Metaphors
User Control

Question 128

Navigation Hierarchy (3)

Answer 128

Hierarchical
Flat
Content Driven or Experience Driven

Question 129

Navigation Design Guidelines (5)

Answer 129

Design an information structure that makes it fast and easy to get to content

Use standard navigation components

Use a navigation bar to traverse a hierarchy of data

Use a tab bar to present peer categories of content functionality

Use the proper transition style

Question 130

You can remove an item from a set by calling the set’s____method

Answer 130

remove(_:)

if let removedGenre = favoriteGenres.remove(“Rock”) {
 print(“(removedGenre)? I’m over it.”)
} else {
 print(“I never much cared for that.”)
}

Question 131

To check whether a set contains a particular item, use the____ method


Answer 131

contains(_:)

if favoriteGenres.contains(“Funk”) {
 print(“I get up on the good foot.”)
} else {
 print(“It’s too funky in here.”)
}
// Prints “It’s too funky in here.”

Question 132

You can iterate over the values in a set with a____

Answer 132

for-inloop

for genre in favoriteGenres {
 print(“(genre)”)
}
// Classical
// Jazz
// Hip hop


Question 133

Swift’sSettype doesn’t have a defined ordering. To iterate over the values of a set in a specific order, use the____ method

Answer 133

sorted()

for genre in favoriteGenres.sorted() {
 print(“(genre)”)
}
// Classical
// Hip hop
// Jazz

Question 134

A ____ stores associations between ____ of the same type and ____ of the same type in a collection with no defined ordering

Answer 134

dictionary
keys
values

Question 135

Each value is associated with a unique ____, which acts as an ____ for that value within the dictionary

Answer 135

key
identifier

Question 136

Unordered collections of key-value associations

Answer 136

Dictionary

Question 137

Code:
Create an empty dictionary

Answer 137

var namesOfIntegers: [Int: String] = [:]. //its keys are Int value and its values are of type String

Question 138

You find out the number of items in aDictionaryby checking its read-only____ property

Answer 138

count

var airports = [“YYZ”: “Toronto Pearson”, “DUB”: “Dublin”]
print(“The airports dictionary contains (airports.count) items.”)

Question 139

Use the Boolean____ property as a shortcut for checking whether thecountproperty is equal to0

Answer 139

isEmpty

Question 140

You can add a new item to a dictionary with subscript syntax. Use a new ____ of the appropriate type as the subscript index, and assign a new value of the appropriate type

Answer 140

key

var airports = [“YYZ”: “Toronto Pearson”, “DUB”: “Dublin”]
airports[“LHR”] = “London”

Question 141

You can also use subscript syntax to ____ the value associated with a particular key

Answer 141

change

var airports = [“YYZ”: “Toronto Pearson”, “DUB”: “Dublin”, “LHR”: “London”]
airports[“LHR”] = “London Heathrow”

Question 142

Remove a key-value pair from a dictionary by assigning a value of ____ for that key

Answer 142

nil
airports[“APL”] = nil

Question 143

Code:
Iterating over a dictionary

Answer 143

for (airportCode, airportName) in airports {
 print(“(airportCode): (airportName)”)
}

Question 144

____ are self-contained chunks of code that perform a specific task

Answer 144

Functions

Question 145

The ____ name is used in the implementation of the function

Answer 145

parameter

Question 146

Type of value that the function takes as input

Answer 146

parameter

Question 147

It’s used when calling the function

Answer 147

Argument

Question 148

To use a function, you “call” that function with its name and pass it input values (known as____) that match the types of the function’s ____

Answer 148

arguments
parameters

Question 149

What does the following mean?
Functions with an implicit return

Answer 149

it means that it’s NOT necessary to write the return keyword

func greeting(for person: String) -> String {

“Hello, “ + person + “!”

}

Question 150

Each function parameter has both an____ labeland a____ name. The ____ label is used when calling the function; each argument is written in the function call with its argument label before it. The ____ name is used in the implementation of the function. By default, parameters use their ____ name as their argument label

Answer 150

argument
parameter
argument
parameter
parameter

Question 151

You can define a____ for any parameter in a function by assigning a value to the parameter after that parameter’s type. If a default value is defined, you can ____ that parameter when calling the function

Answer 151

default value
omit

Question 152

Variadic Parameter

Answer 152

(…) the three dots are called an ellipsis.
A function can have only one variadic parameter

func arithmeticMean(_ numbers: Double…) -> Double {
 var total: Double = 0


for number in numbers {

total += number
 }

return total / Double(numbers.count)

}


arithmeticMean(1, 2, 3, 4, 5)

// returns 3.0, which is the arithmetic mean of these five numbers

Question 153

In-Out Parameters -> Variadic parameters ____ be marked as inout, &&

Answer 153

can’t

Question 154

____ A function that doesn’t have a return, This is simply an ____, which is written as____

Answer 154

Void
empty tuple
()

Question 155

Function’s signature:

Answer 155

Combination of its name plus its argument names and types, plus its return type

Question 156

Function type =

Answer 156

parameter types + return type

Question 157

Function Parameters are ____ by default.

Answer 157

constants

Question 158

Trying to change the value of a function parameter from within the body of that function results in a compile-time error.

This means that you can’t change the value of a parameter by mistake.

If you want a function to modify a parameter’s value, and you want those changes to persist after the function call has ended, define that parameter as an____ parameterinstead. ____ parameters can’t have default values, and variadic parameters can’t be marked asinout

Answer 158

in-out
In-out

func swapTwoInts(_ a: inout Int, _ b: inout Int) {

let temporaryA = a

a = b

b = temporaryA

}

var someInt = 3
var anotherInt = 107
swapTwoInts(&someInt, &anotherInt)

print(“someInt is now (someInt), and anotherInt is now (anotherInt)”)


Question 159

Nested Functions:

Answer 159

Nested functions are hidden from the outside world by default, but can still be called and used by their enclosing function.

An enclosing function can also return one of its nested functions to allow the nested function to be used in another scope

Question 160

____are functions that are associated with a particular type. Classes, structures, and enumerations can all define instance ____, which encapsulate specific tasks and functionality for working with an instance of a given type

Answer 160

Methods
methods

Question 161

inside a class, structure or enum, are called ____

Answer 161

methods

Question 162

____are functions that belong to instances of a particular class, structure, or enumeration

Answer 162

Instance methods

Question 163

Structures and enumerations are ____ types. By default, the properties of a ____ type can’t be modified from within its instance methods

Answer 163

value

Question 164

if you need to modify the properties of your structure or enumeration within a particular method, you can opt in to____behavior for that method

Answer 164

mutating

Classes don’t need this keyword in the methods, because are reference type.

Question 165

Control Flow

Answer 165

For-In Loop
While Loop
repeat-while

Conditional statements:
If/else
Switch

Question 166

To iterate over the items in array, a dictionary to access its key-value pairs, numeric ranges

Answer 166

For-In Loop

Question 167

You can use this syntax to iterateanycollection, including your own classes and collection types, as long as those types conform to the____protocol.

Answer 167

Sequence

Question 168

Performs a set of statements until a condition becomes false

Answer 168

While Loop

Question 169

These kind of loops are best used when the number of iterations isn’t known before the first iteration begins

Answer 169

While Loop

Question 170

Evaluates its condition at the end of each pass through the loop

Answer 170

repeat-while

repeat {

<#statements#>

} while <#condition#>

Question 171

Conditional statements:

Answer 171

If/else
Switch

Question 172

Considers a value and compares it against several possible matching patterns

Clue: it’s a conditional statement

Answer 172

switch

Question 173

Everyswitchstatement must be____

Answer 173

exhaustive

Question 174

____: Aswitchcase can name the value or values it matches to temporary constants or variables, for use in the body of the case. This behavior is known as____ , because the values are bound to temporary constants or variables within the case’s body

Answer 174

Value bindings

Question 175

Aswitchcase can use a____clause to check for additional conditions

Answer 175

where

Question 176

____: Multiple switch cases that share the same body can be combined by writing several patterns aftercase. ____ can also include value bindings

Answer 176

Compound cases

let someCharacter: Character = “e”


switch someCharacter {

case “a”, “e”, “i”, “o”, “u”:

print(“(someCharacter) is a vowel”)

case “b”, “c”, “d”, “f”, “g”, “h”, “j”, “k”, “l”, “m”,
”n”, “p”, “q”, “r”, “s”, “t”, “v”, “w”, “x”, “y”, “z”:

print(“(someCharacter) is a consonant”)

default:

print(“(someCharacter) isn’t a vowel or a consonant”)
}
//

Prints “e is a vowel”

Question 177

____: Change the order in which your code is executed, by transferring control from one piece of code to another. Swift has 5 control statements

Answer 177

Control Transfer Statements

Question 178

Control Transfer Statements (5)

Answer 178

Continue
Break
Fallthrough
Return
Throw

Question 179

Continue
(Control Transfer Statement)

Answer 179

Tells a loop to stop what it’s doing and start again at the beginning of the next iteration through the loop

Question 180

Break
(Control Transfer Statement)

Answer 180

Ends execution of an entire control flow statement immediately.

Thebreakstatement can be used inside aswitchor loop statement when you want to terminate the execution of theswitchor loop statement earlier than would otherwise be the case

                    * Break in a Loop statement
                    * Break in a Switch Statement

Question 181

Fallthrough
(Control Transfer Statement)

Answer 181

In Swift,switchstatements don’t fall through the bottom of each case and into the next one. That is, the entireswitchstatement completes its execution as soon as the first matching case is completed

Question 182

Early exit (____): A____ statement, like anifstatement executes statements depending on the Boolean value of an expression.

You use a ____statement to require that a condition must be true in order for the code after the____ statement to be executed. Unlike anifstatement, a____ statement always has anelseclause — the code inside theelseclause is executed if the condition isn’t true

Answer 182

guard

Question 183

Model custom types that define a list of possible values

Answer 183

Enum

Question 184

If a value (known as a____) is provided for each enumeration case, the value can be a string, a character, or a value of any integer or floating-point type

Clue: Enum

Answer 184

rawvalue

Question 185

Enumerations can conform to ____ to provide standard functionality

Answer 185

protocols