Collections #

This page contains information and coding exercises for collections.

💻 Open up the pseudocode compiler in a new tab. You will be using this website to complete the exercises below.

Examples #

Creating a new Collection #

NAMES = new Collection()

Adding to Collections #

NAMES.addItem("Bob")
NAMES.addItem("Dave")
NAMES.addItem("Betty")
NAMES.addItem("Kim")
NAMES.addItem("Debbie")
NAMES.addItem("Lucy")

Important collection methods #

MYCOLLECTION.resetNext() // go back to the start of the collection
MYCOLLECTION.hasNext() // checks if there are any elements left. returns true/false
MYCOLLECTION.getNext() // returns the next item in the collection
MYCOLLECTION.contains(THING) // checks if THING is in the collection
MYCOLLECTION.remove(THING) // removes a thing to the collection

Looping through a Collection #

MYCOLLECTION.resetNext() // go to the start of the collection
loop while MYCOLLECTION.hasNext() // keep looping if there are more elements
    THING = MYCOLLECTION.getNext() // access the item stored in the collection
    output THING // so something with the item you accessed
end loop

Practice Exercises #

Exercise 1: Typhoon Warning System #

Imagine that we want to store the hourly windspeed during a typhoon into a collection.

💻 Write a program that determines the warning signal based on windspeed

Create a collection
Add 10 windspeeds to it
Loop through the collection
For each windspeed, tell the user which signal is hoisted

Code	Windspeed
T3	41-62 km/h
T8	63-117 km/h
T10+	118 km/h or more

Here is an example output:

T3
T8
T8
T3
T3
T8
T10+
T8
T8
T3

💻 Now add in a variable to keep track of the hour. Output the hour along with the typhoon signal.

Hour 1 T3
Hour 2 T8
Hour 3 T8
Hour 4 T3
Hour 5 T3
Hour 6 T8
Hour 7 T10+
Hour 8 T8
Hour 9 T8
Hour 10 T3

Reminder: you can print multiple things on one line using a comma

FRIEND = Jacob
output "hello", FRIEND

Exercise 2: Dividing Teams #

💻 Create two teams of students by alternating through the collection of names

Create a collection
Add 10 students to it
Output team one
Output team two

Here is an example:

STUDENTS = new Collection()
STUDENTS.addItem("Bob")
STUDENTS.addItem("Dave")
STUDENTS.addItem("Betty")
STUDENTS.addItem("Kim")
STUDENTS.addItem("Debbie")
STUDENTS.addItem("Lucy")

output:

TEAM 1
- Bob
- Betty
- Debby
-------
TEAM 2
- Dave
- Kim
- Lucy

Exercise 3: First/Last Names #

A company has 600 employees whose names are currently stored using a collection called NAMES. The names are stored as surname, first name. For example: Smith, Jane, Uysal, Rafael, Ahmed, Ishmael, Jonsonn, Sara, …

💻 Construct a pseudocode algorithm that will store the surnames in one array and first names in another.

Output both arrays at the end