Class Notes Week 4

Acknowledgement of Traditional Owners

QUT acknowledges the Turrbal and Yunggra as the first nation owners of the lands where QUT now stands.
Respect is paid to their elders, laws, customs, and creation spirits.
Recognition that these lands have always been places of teaching, research, and learning.
QUT acknowledges the important role that Aboriginal and Torres Strait Islander people play within the QUT community.

Week Four Overview

First week back from the cyclone.
First assignment is officially due tonight, with a 48-hour grace period.
- Gradescope is separate from the QUT network, so only one date can be set.
- The date is set for tonight, but a 48-hour extension is provided by default.

Lecture Topics

Briefly review Assignment One.
Review Tutorial Four (Week Three).
Guest speaker: Richard from the student support group (peer support).
Brief review of the first four weeks.
Tim covers what's to come in the next few weeks.

Assignment One

Due since week one.
Official due date is tonight.
Gradescope was temporarily broken, but a workaround was provided.
The issue has been officially fixed (as of overnight).
A link to Gradescope status is provided to track predicted outages.

Gradescope Status Page

Core functionality and auto grader status are available.
Gradescope has different domains (e.g., .com, .ca).
.ca is for Canada, while .com, .eu, and .au are for other users.
Outages may not be fully disclosed, but some information is better than none.

Gradescope Issue Escalation

The issue was escalated by instructors after it was not addressed on the weekend.
Multiple units use Gradescope, primarily in computer science and engineering.
The issue was escalated within QUT to those who signed the Gradescope license.

Resubmission and Code Quality

If Gradescope issues persist, resubmit the code multiple times.
Test locally to identify errors.
While the code isn't executed during errors, it is copied.

Assignment Details

Five questions: Chicken and eggs, counting largest number, warmer or colder, counting vowels and consonants, and the Manhattan block.
Unlimited submissions are allowed.
If encountering errors and stress, apply for an extension.
QUT is aware of the issue, so extensions will be granted.
Gradescope can only set one due date, but submissions will still be accepted after the due date with an extension.
Questions one, two, and three could be answered after week two.
Questions four and five can be answered after week three.
Assignment submissions have been increasing significantly.

Gradescope Code Viewing

Gradescope allows viewing of submitted code, even if it wasn't executed.
This allows for code quality assessment in the second assignment.

Contact and Support

Queries can be sent today, but weekend replies may be delayed.

Week Three Tutorial Review: Shopping List

Skeleton code provided for input/output and string formats.
Code begins and ends with equal signs to delineate the program.
The program gets the number of items from the customer (numItems).
If statement: if numItems is greater than zero, the program continues; otherwise, it doesn't proceed.

For Loop for Entering Items

A for loop is used to enter items.
Condition statement: I < numItems (ensure it's not less than or equal to avoid out-of-bounds errors).
Initial value of the control variable is zero, and it's incremented each time.
Items are added to the array using input from the ReadLine statement.

Array Details

The array called items is a string array.
Arrays in C# can only hold one type of data.

Debugging

Debugging can be done using the debugger or simple console input/output.
Example: bread is stored at index zero, milk at index one, etc.
Arrays count from zero.

Sorting Array

The Array.Sort method is used to sort the array.
IDEs like Visual Studio can auto-complete the method.
The program writes the sorted items to the screen using a specific format.
The numbers zero and one in the format strings refer to what to print out.
Strings are sorted alphabetically based on character values.
Characters are stored as numbers, with 'a' having a higher numeric value than 'z'.
Uppercase and lowercase letters have different numeric values.
To sort differently, ensure all cases are the same.

Example of Sorting

Tea, milk, and bread are entered, and the list is reordered alphabetically.
Different cases affect the sorting order; uppercase letters come first.

Entering a List of Integers Separated by Commas

Similar start and end to previous tasks.
Use the Split string method to split the input.
Delimiter is a comma.
Create a new array called values.
Convert each item to a new index in the values array.
Print things out to the console.

Redirection

When you run it type in the execution, but the exe.
That actually calls the DLL file.

Math Studio

Pixelizing common mathematical operations.
Compound arrays: arrays within arrays.
Use a double for loop to print each index.

Alternative Implementation for Minus Symbol

Create a new array with everything initially set to an empty space,
Set a single row of the array, assigning the elements in that row specific characters.
Use the array with the new element values.
This is good for a 2D array when you want to change positions instead of creating a new array each time.
Question five of your assignment.

Guest Speaker: Richard from Student Support

Richard organizes peer support sessions.
CAB201 students often seek support due to the subject's difficulty.
Coding problems can arise from a single incorrect line.

Stimulate Program

Dedicated support sessions are run to answer assignment questions.
Help is often needed with assessments due to time constraints.
The support is available throughout the semester, especially around assessments.
Stimulate.qut.edu.au

STEM Support

Support is available for any STEM question the university teaches.
CAB201 has many peers available, but support is limited on Friday afternoons.
Online support is available for those who can't make it to campus via the "Request PLF" button.

Opportunities and Motivation

Students should explore career options and projects of interest.
Motivation and determination are crucial as the course progresses.
Consider the type of projects you want to work on and who you want to work with.
Opportunities exist to do challenging projects and build a portfolio early.

Language Learning

Practice and fatigue are essential for improving public speaking skills.
Services like Speakeasy are available for free to improve public speaking.

Study Skills

Help is available for study skills if things aren't sticking.
Services can assist with study methods and time management.
Empirically based methods for retention and content sticking are available.
Student fees cover these services, so utilize them.

Review of Weeks One to Four

The unit is split into three parts.
The first part focuses on translating previous programming knowledge to C#.
The second part covers object-oriented design and implementation.
The final part reviews and reflects on previous work.
The next four weeks will be a step up in learning.

Week One: Data and Types

Different types: string, int, double, and float.
Ways to format them on a string and looking at the different conversions for a string & vice versa.

Week Two: Selection and Iteration

Selection: if, else, and switch statements.
Iteration: while, do-while, and for loop.

Week Three: Arrays

One-dimensional, parallel, and model dimension.
Main array methods: Sort, Reverse, and Search.
Collections: List (dynamic array) and Dictionary (key-value pair).

Algorithms

Sequential and segmented using loops and if statements.

Week Four: Command Line Arguments and Debugging

Directories and files: reading and writing.
Testing: valid, invalid, and boundary cases.
Equals: testing values at the threshold.
Absence testing: testing collections with no items.

Advice for the Next Eight Weeks

New content builds upon previous content; knowledge from data types is crucial for collections and files.
Previous knowledge is required to understand what's going on in the previous week because and this will get harder and harder as the semester goes on.
Reach out for help from instructors, tutors, Simulate, and peers.

Object-Oriented Programming (OOP) Overview

Classes and Objects
Classes: Templates, blueprints, cookie cutters
Objects: Cookies, widgets, things built from those templates/

Importance of Classes in Scaling Up Software Development

Classes are self-contained packages of related data

Attributes of Classes:

Methods
Fields
Properties

Example System Application: Employees

Each employee:

Name
Address
Date of birth

Encapsulation of an Employee Class:

Bundles the information and can use the variables at the same time

Key Relationship to Object Oriented Design:

How programs are buit differently
Analyzing the system
The new classes

Key Aspects: What do these classes need to know & What do these classes need to do?

So, for example:
An employee may need to do a "thing" and "name" that employee to be saved in a direct method.
Static Keyword for Methods:
A method that doesn't need a direct link to each employee

Static Keyword for Fields:

Each field is assigned to the employee class not on each individual employee
Public or Private variables

Global variable: (BAD!!! - if can be avoided, should be)

The Concept of Null and Nullability:

What objects are missing vs what are active in your code.
This section of the notes will show you how to fix the errors of nullability being an issue in your code, which can be solved in a few different manners
Proper written C# will need to fix these warnings!!!

Types you should be checking:

Nullable String Type:

String?

The Null coalescing operator - to use blank strings instead of Null values:

Console.ReadLine?? "\""

Make sure to check the null video when that goes up for those details

From now on we need to fix the warnings