Control Flow

Question 1

Use _____ and _____ to make conditionals,

Answer 1

if, switch

Question 2

use _____-in, _____, _____, and _____-while to make loops.

Answer 2

for-in, for, while, repeat-while

Question 3

Parentheses around the condition or loop variable are _____.

Answer 3

optional

Question 4

An optional value either contains a value or contains nil to indicate that a value is missing. Type _____ after the type of a value to mark the value as optional.

Answer 4

?

var optionalString: String? = “Hello”

Question 5

_____ support any kind of data and a wide variety of comparison operations—they aren’t limited to integers and tests for equality.

Answer 5

Switches

Question 6

You use _____ to iterate over items in a dictionary by providing a pair of names to use for each key-value pair.

Answer 6

for-in

Question 7

_____ are an unordered collection, so their keys and values are iterated over in an arbitrary order.

Answer 7

Dictionaries

Question 8

Use _____ to repeat a block of code until a condition changes. The condition of a loop can be at the end instead, ensuring that the loop is run at least once.

Answer 8

while

Question 9

You can keep an index in a loop—either by using _____ to make a range of indexes or by writing an explicit initialization, condition, and increment.

Answer 9

..<

These two loops do the same thing: