Swift 2021 _ Tutorialpoint

Question 1

Define Swift 4?

Answer 1

Apple programming Language - designed for iOS and OSX development

Question 2

Most recent API compatible?

Answer 2

iOS 6

OSX 10.8

Question 3

Using Swift, is actually fantastic at?

Answer 3

Developing iOS and OSX developments

Question 4

Using Swift, provides seamless access?

Answer 4

Existing Cocoa frameworks

Question 5

Using Swift, unifies what?

Answer 5

Procedural and Object-oriented parts of the lanuage

Question 6

Is a separate library required for certain functionalities?

Answer 6

NOPE!

Question 7

Swift 4 comes with X that helps programmers to write and execute code?

Answer 7

Playground!

Question 8

Getting Started

Answer 8

• install XCode
• open it
• select ‘Get started with a playground’

Question 9

Swift ‘Hello World’ - Playgound

Answer 9

import UIKit
var str = "Hello, playground"

Question 10

Swift ‘Hello World’ - OSX

Answer 10

import Cocoa
var str = "Hello, playground"

Question 11

‘Hello World’s difference??

Answer 11

import UIKit
VS
import Cocoa

Question 12

Semicolon - single line - required?

Answer 12

Nope

but optional

Question 13

Semicolon - for multi lined?

Answer 13

Required!

Question 14

Special Characters not allowed as Identifiers?

Answer 14

@, $, %

Question 15

Is Swift case sensitive?

Answer 15

YEs

Question 16

How to use a reserved word as an identifier?

Answer 16

class

Use ( ` ) - backtick

Question 17

Whitespaces?

Answer 17

Totally ignored!

Question 18

Type of Whitespaces?

Answer 18

blanks, tabs, newline characters, AND comments

Question 19

Correct use of spacing?

Answer 19

int fruit = apples +oranges //is a wrong statement

int fruit = apples + oranges //is a Correct statement

Question 20

Printing in Swift

Answer 20

3 properties:

• Items
• Separator
• Terminator

print(‘hello world”)

Question 21

Type Aliases

Answer 21

typealias newname = type
eg
typealias Feet = Int

Question 22

Type Safety means?

Answer 22

if part of your code expects a String you cannot pass it an ‘int’ by mistake

Question 23

Cannot assign error?

Answer 23

main.swift:2:8: error: cannot assign value of type ‘String’ to type ‘Int’
varA = “This is hello”

Question 24

Type Annotations are spelled out:

Answer 24

var variableName: =

Question 25

Eg of Printing Variables

Answer 25

var varA = "Godzilla"
var varB = 1000.00

print(“Value of (varA) is more than (varB) millions”)

Question 26

What’s special about Optional types?

Answer 26

They are a type on their own.

Question 27

Values of Optionals?

Answer 27

-None
-Some(T)
T - is an associated value of the data type available

Question 28

Optional - types

Answer 28

To make values ‘nil’

Question 29

Tuples are?

Answer 29

Used to group multiple values in a single compound Value

Question 30

Tuple types

Answer 30

Can be any type

Question 31

Tuple example

Answer 31

var TupleName = (Value1, value2,… any number of values)

Question 32

Tuple declaration

Answer 32

var error501 = (501, “Not implemented”)

Question 33

Tuple reference index(es)

Answer 33

print(“The code is(error501.0)”)

print(“The definition of error is(error501.1)”)

Question 34

What kind of data type can be made constant?

Answer 34

Any and all

Question 35

Logical Operators

Answer 35

&&( A && B)
|| (A || B)
! (A&&B)

Question 36

Ternary

Answer 36

Exp1 ? Exp2 : Exp3;

Question 37

Finding String length?

Answer 37

var varA = “Hello, Swift 4!”

print( “(varA), length is ((varA.count))” )

Question 38

How to iterate over string using loops?

Answer 38

for chars in “ThisString” {
print(chars, terminator: “ “)
}
output: T h i s S t r i n g

Question 39

String: isEmpty( )

Answer 39

A Boolean value that determines whether a string is empty or not.

Question 40

String: hasPrefix(prefix: String)

Answer 40

Function to check whether a given parameter string exists as a prefix of the string or not.

Question 41

String:hasSuffix(suffix: String)

Answer 41

Function to check whether a given parameter string exists as a suffix of the string or not.

Question 42

String: toInt()

Answer 42

Function to convert numeric String value into Integer.

Question 43

String: count()

Answer 43

Global function to count the number of Characters in a string.

Question 44

String: utf8

Answer 44

Property return a UTF-8 representation of a string.

Question 45

String: utf16

Answer 45

Property to return a UTF-16 representation of a string.

Question 46

String: unicodeScalars

Answer 46

Property to return a Unicode Scalar representation of a string.

Question 47

String: +

Answer 47

Operator to concatenate two strings, or a string and a character, or two characters.

Question 48

String: +=

Answer 48

Operator to append a string or character to an existing string.

Question 49

String: ++

Answer 49

Operator to append a string or character to an existing string.

Question 50

String: ==

Answer 50

Operator to determine the equality of two strings.

Question 51

String:

Answer 51

Operator to perform a lexicographical comparison to determine whether one string evaluates as less than another.

Question 52

String: startIndex

Answer 52

To get the value at starting index of string.

Question 53

String: endIndex

Answer 53

To get the value at ending index of string.

Question 54

String: Indecies

Answer 54

To access the indeces one by one. i.e all the characters of string one by one.

Question 55

String: insert(“Value”, at: position)

Answer 55

To insert a value at a position.

Question 56

String:
remove(at: position)

removeSubrange(range)

Answer 56

to remove a value at a position, or to remove a range of values from string.

Question 57

String: reversed( )

Answer 57

returns the reverse of a string

Question 58

Define Char

Answer 58

in Swift it’s a single character String literal

Question 59

For-in loop example

Answer 59

for ch in “Hello” {
print(ch)
}

Question 60

How to concatenate Strings?

Answer 60

var varA:String = “Hello “
let varB:Character = “G”

varA.append( varB )

print(“Value of varC = (varA)”)

Question 61

How strict is Swift’s checking a wrong type into an array?

Answer 61

Very strict! - Not all allowed, even by mistake

Question 62

How to make an Array?

Answer 62

var someArray = [SomeType]{ }

Question 63

How to Access an Array?

Answer 63

var someVar = someArray[index]

Question 64

How to add to existing Array?

Answer 64

array.append( )

Question 65

How to modify an Element at index?

Answer 65

someInt[2] = 44
//resets

Question 66

How to enumerate( ) an array with for-in loop?

Answer 66

var someStrs = String

someStrs.append(“Apple”)
someStrs.append(“Amazon”)
someStrs += [“Google”]

for (index, item) in someStrs.enumerated() {
print(“Value at index = (index) is (item)”)

Question 67

How to add 2 Arrays?

Answer 67

var intsA = [Int](count:2, repeatedValue: 2)
var intsB = [Int](count:3, repeatedValue: 1)

var intsC = intsA + intsB
for item in intsC {
   print(item)
}

Question 68

Define ‘sets’?

Answer 68

Swift 4 sets are used to store distinct values of same types but they don’t have definite ordering as arrays have.

Question 69

Do sets allow for same variables?

Answer 69

NOPE, only distinct

Question 70

How to create a ‘set’?

Answer 70

var someSet = Set() //Character can be replaced by data type of set.

Question 71

Sets: count

Answer 71

someSet.count // prints the number of elements

Question 72

Sets: insert(‘c’)

Answer 72

someSet.insert(“c”) // adds the element to Set.

Question 73

Sets: isEmpty

Answer 73

someSet.isEmpty // returns true or false depending on the set Elements.

Question 74

Sets: remove(‘c’)

Answer 74

someSet.remove(“c”) // removes a element , removeAll() can be used to remove all elements

Question 75

Sets: contains(‘c’)

Answer 75

someSet.contains(“c”) // to check if set contains this value.

Question 76

Sets: Iterate - no order

Answer 76

for items in someSet {
print(someSet)
}

Question 77

Sets: Iterate - ordered

Answer 77

for items in someSet.sorted() {
print(someSet)
}

Question 78

Swift - define dicitionaries

Answer 78

dictionaries are used to store unordered lists of values of the same type.

Question 79

How are ‘dictionaries’ different than ‘array’?

Answer 79

Unlike items in an array, items in a dictionary do not have a specified order. You can use a dictionary when you need to look up values based on their identifiers

Question 80

Basic ‘dictionary’ syntax?

Answer 80

var someDict = KeyType: ValueType

Question 81

Simple ‘dictionary’ example?

Answer 81

var someDict = Int: String

Question 82

Dictionary: Sequence Based Initialization

Answer 82

Swift 4 allows you to create Dictionary from arrays (Key-Value Pairs.)

Question 83

Dictionary: Filtering

Answer 83

Swift 4 allows you to filter values from a dictionary.

Question 84

Dictionary: Dictionary Grouping

Answer 84

Swift 4 allows you to create grouping of Dictionary values.

Question 85

Dictionary: Accessing Dictionaries

Answer 85

You can retrieve a value from a dictionary by using subscript syntax, passing the key of the value you want to retrieve within square brackets immediately after the name of the dictionary

Question 86

Dictionary: Accessing Dictionary - how to

Answer 86

var someVar = someDict[key]

Question 87

Dictionaries: Modifying Dictionaries

Answer 87

You can use updateValue(forKey:) method to add an existing value to a given key of the dictionary. This method returns an optional value of the dictionary’s value type.

Question 88

Dictionaries: Modifying Dictionaries - how to

Answer 88

updateValue(forKey:)

method to add an existing value to a given key of the dictionary.

Question 89

Dictionaries: Remove Key-Value Pairs

Answer 89

method to remove a key-value pair from a dictionary.

Question 90

Dictionary: for-in loop

Answer 90

Used to loop over elements used in a dictionary

Question 91

Dictionary: count property

Answer 91

Int of the number of items in a ‘dictionary’

Question 92

Dictionary: Empy

Answer 92

var someDict3:[Int:String] = Int:String

Question 93

Function syntax?

Answer 93

func funcname(Parameters) -> returntype {

Question 94

Function Declaration

Answer 94

tells the compiler about a function’s name, return type, and parameters.

Question 95

Function Definition

Answer 95

It provides the actual body of the function.

Question 96

Swift 4: Functions

Answer 96

Defined by ‘func’ keyword

Question 97

Function Parameter is what?

Answer 97

Function is called by name and passes input values (knows as arguments)

Question 98

A Function return is waht?

Answer 98

Values passed back from the ‘output’ of the function

Question 99

Function Syntax?

Answer 99

func funcname(Parameters) -> returntype {

}

Question 100

Function: return example

Answer 100

func student(name: String) -> String {
   return name
}

print(student(name: “First Program”))
print(student(name: “About Functions”))

Output:
First Program
About Functions

Question 101

Calling Function: Example

Answer 101

func display(no1: Int) -> Int {
   let a = no1
   return a
}

print(display(no1: 100))
print(display(no1: 200))

Output:
100
200

Question 102

Function Without Parameter: Syntax

Answer 102

func funcname() -> datatype {
   return datatype
}

Question 103

Function Without Parameter: Example

Answer 103

func votersname() -> String {
   return "Alice"
}
print(votersname()) 

Output
Alex

Question 104

Functions with Return Values

Answer 104

func ls(array: [Int]) -> (large: Int, small: Int) {
   var lar = array[0]
   var sma = array[0]

   for i in array[1.. lar {
         lar = i
      }
   }
   return (lar, sma)
}

let num = ls(array: [40,12,-5,78,98])
print("Largest number is: \(num.large) and smallest number is: \(num.small)")

Output
Largest number is: 98 and smallest number is: -5

Question 105

Functions without Return Values

Answer 105

func sum(a: Int, b: Int) {
   let a = a + b
   let b = a - b
   print(a, b)
}

sum(a: 20, b: 10)
sum(a: 40, b: 10)
sum(a: 24, b: 6)

Output:
30 20
50 40
30 24

Question 106

Local parameter names are

Answer 106

accessed inside the function alone

Question 107

External Parameter Names

Answer 107

allow us to name a function parameters to make their purpose more clear

Question 108

Variadic Parameters

Answer 108

When we want to define function with multiple number of arguments, then we can declare the members as ‘variadic’ parameters. Parameters can be specified as variadic by (···) after the parameter name.

Question 109

Variadic Parameters: example

Answer 109

func vari(members: N...){
   for i in members {
      print(i)
   }
}

vari(members: 4,3,5)
vari(members: 4.5, 3.1, 5.6)
vari(members: “Swift 4”, “Enumerations”, “Closures”)

Output:
4
3
5
4.5
3.1
5.6
Swift 4
Enumerations
Closures

Question 110

let VS var

Answer 110

that ‘let’ keyword is used to declare constant parameters and variable parameters is defined with ‘var’ keyword

Question 111

inout’ keyword

Answer 111

declared to retain the member values
functionality to retain the parameter values even though its values are modified after the function call. At the beginning of the function parameter definition

Question 112

‘&’ before a variable name

Answer 112

refers that we are passing the argument to the in-out parameter.

Question 113

in-out Example

Answer 113

func temp(a1: inout Int, b1: inout Int) {
   let t = a1
   a1 = b1
   b1 = t
}

var no = 2
var co = 10
temp(a1: &no, b1: &co)
print("Swapped values are \(no), \(co)")

Output:
Swapped values are 10, 2

Question 114

Void functions do what?

Answer 114

Functions may also have void data types and such functions won’t return anything.

Question 115

Call we call a function as a parameter?

Answer 115

Yest, we can also pass the function itself as parameter types to another function.

Question 116

Generic syntax to define closure?

Answer 116

{
(parameters) −> return type in
statements
}

Question 117

Single Expression Implicit Returns

Answer 117

To return a Single expression statement in expression closures ‘return’ keyword is omitted in its declaration part.

Question 118

Known Type Closures

Answer 118

Consider the addition of two numbers. We know that addition will return the integer datatype.

Question 119

Declaring Shorthand Argument Names as Closures

Answer 119

Swift 4 automatically provides shorthand argument names to inline closures, which can be used to refer to the values of the closure’s arguments by the names $0, $1, $2, and so on.

Question 120

Closures as Operator Functions

Answer 120

Swift 4 provides an easy way to access the members by just providing operator functions as closures. In the previous examples keyword ‘Bool’ is used to return either ‘true’ when the strings are equal otherwise it returns ‘false’.

Question 121

Closures as Trailers

Answer 121

Passing the function’s final argument to a closure expression is declared with the help of ‘Trailing Closures’.

Question 122

A nested function captures −

Answer 122

• Outer function arguments.

- Capture constants and variables defined within the Outer function.

Question 123

Enumeration Types - example

Answer 123

For example, the four suits in a deck of playing cards may be four enumerators named Club, Diamond, Heart, and Spade, belonging to an enumerated type named suit. If a variable V is declared having suit as its data type, one can assign any of those four values to it.

Question 124

Enumeration in Swift 4 also resembles the structure of C and Objective C.

Answer 124

• It is declared in a class and its values are accessed through the instance of that class.
• Initial member value is defined using enum intializers.
• Its functionality is also extended by ensuring standard protocol functionality.

Question 125

Enum Example!

Answer 125

enum names {
case Swift
case Closures
}

var lang = names.Closures
lang = .Closures

switch lang {
   case .Swift:
      print("Welcome to Swift")
   case .Closures:
      print("Welcome to Closures")
   default:
      print("Introduction")
}

Question 126

Associated Values

Answer 126

• Different Datatypes
• Ex: enum {10,0.8,”Hello”}
• Values are created based on constant or variable
• Varies when declared each time

Question 127

Raw Values

Answer 127

• Same Datatypes
• Ex: enum {10,35,50}
• Prepopulated Values
• Value for member is same

Question 128

Example of Structure?

Answer 128

In Structure the variable values are copied and passed in subsequent codes by returning a copy of the old values so that the values cannot be altered.