COMP9001 — Chapter 1 Supplement

Foundations & Quick Checks

A compact revision page for the key definitions, workflow, commands, and interpreter concepts introduced in Lecture 1.

Program Definition

Definition

A program is a set of instructions for a computer to execute in sequence to perform a certain task.

Which part of the definition makes order explicitly important?

“perform a certain task”

“execute in sequence”

Sequence and Logic

Lecture use of examples

Joining class or following a recipe works only when the actions are ordered correctly. The course uses these examples to introduce algorithmic thinking before code syntax.

Why are everyday instruction lists useful in an intro programming lecture?

They show that programming starts with precise step-by-step thinking

They replace the need to learn code entirely

Source Code Translation

Item

Term

Meaning

Text file

Source code

Human-readable program text written in a programming language

Binary execution form

Machine code

The form the hardware can actually execute

Whole program first

Compiler

Translates the source code before running

Line by line

Interpreter

Translates while the program is running

What is the lecture’s main distinction between a compiler and an interpreter?

A compiler translates the full program before running, while an interpreter translates during execution

Only one of them translates code at all

Tools and Commands

Command

Usage

Purpose

pwd

where am I?

Show the current directory

ls

view contents

List files and folders

mkdir

make directory

Create a folder

cd

change directory

Move to another location

touch

create file

Make a new file like hello.py

mv / cp

move / copy

Manage files

First Program Workflow

Three steps

1. Create a .py file. 2. Write code into the file. 3. Run the file.

Which step comes immediately after creating the file?

Write code into the file

Run the file immediately

Output and Interpreter

Built-in function

print() is introduced as a built-in function used for text output.

Python shell

Running python3 opens the interpreter, where code can be executed immediately and the results are shown right away.

Why is the interpreter useful for beginners?

It lets you try code immediately and inspect the result

It removes the need to learn Python syntax