Ch 2: Introduction to Swift Programming

Question 1

String interpolation: How is it used to construct a new string value? Hint: 4 steps:
> What it uses
> Starts and ends with
> How to delineate internal parts
> Some parts do not have to be delineated

==> P. 26

Answer 1

> Use a mix of constants, variables, literals, and expressions by including their values inside a string literal.
The enclosing string literal starts and ends with a double quote mark.
Each item that you insert into the string literal is wrapped in a pair of parentheses, prefixed by a backslash ().
The string text inside the double quotes (part of the string literal itself) do not have to be wrapped in parenthesis and prefixed by a ().

Question 2

What are the two ways that Swift knows an identifier’s type?

==> P. 25

Answer 2

1) By type inference

2) By type annotation

Question 3

How does type inference work?

==> P. 25

Answer 3

An identifier (variable, constant, etc.) is given a value. The format of the value supplies type information to Swift.

Question 4

How does type annotation work?

==> P.25

Answer 4

The type of an identifier is explicitly specified in the initializer statement.

Question 5

What are the naming rules for identifiers for variables and constants?

==> P. 26 - 27

Answer 5

Identifiers can contain most valid Unicode characters with the following exceptions:

Typically begin with a lower case letter.
May not start with a number.
Cannot contain whitespace, math symbols, arrows, drawing characters, etc.

Camel case is frequently used.

Question 6

What type of letter do type names begin with?

==> P. 26

Answer 6

Uppercase.

Question 7

Give examples of a variable identifier being declared as follows:
With type inference
With type annotation
With type inference and annotation

==> P. 25

Answer 7

var number1 = 4
var number1: Int
var number1: Int =4

Question 8

Give examples of a constant identifier being declared as follows:
Type inference (via assignment)
With type annotation
With type annotation and assignment

==> P. 27

Answer 8

let number2 = 25
let number2: Int
let number2: Int = 25

Question 9

What is an expression? Give two answers.
One answer is essentially a simplification of the other.

==> P. 28

Answer 9

1) Any portion of a statement that has calculations.
2) Any portion of a statement that has a value associated with it.
* **==> Explore further, find examples

Question 10

What are the six comparison operators?
Hint: They exist in three pairs, with each pair having complementary operators.

==> P. 30

Answer 10

==, != equal to, not equal to
>, < greater than, less than
>=, <= greater than or equal to, less than or equal to

Question 11

What is the format of the simple if statement?

==> P. 29 - 31

Answer 11

if condition {
body of statements
}

Question 12

Are braces required in an if statement?

==> P. 31

Answer 12

Yes - braces are required in an if statement.

Question 13

What are some “extended” comparison operators in addition to the six “normal” ones?

==> P. 30

Answer 13

===  identical to
!==   not identical to

“Identical to” means the two things being compared represent the same object, structure, or enumeration.

Question 14

What represents an empty control statement (such as if)?

==> P. 32

Answer 14

A pair of braces: {}