Introduction to
Programming
CCC101 Computer Programming 1
In this module, you will learn about:
• the fundamentals of computer programming, i.e., how
the computer works, how the program is executed,
how the programming language is defined and
constructed;
• the difference between compilation and
interpretation;
• what Python is, how it is positioned among other
programming languages, and what distinguishes the
different versions of Python.
How does a computer program work?
• A program makes a
computer usable.
• Contemporary computers
excel at executing
fundamental operations
rapidly and repeatedly.
How does a computer program work?
• Example: Calculating average speed during a journey.
• It is necessary to instruct the computer to:
1. accept a number representing the distance;
2. a number representing the travel time;
3. divide the former value by the latter and store the result in
the memory;
4. display the result (representing the average speed) in a
readable format.
• These steps collectively create a program.
• Translation into a language computers understand.
Natural languages vs. programming languages
• A language is a means (and a tool)
for expressing and recording
thoughts.
• Computers have their own language,
too, called machine language, which
is very rudimentary.
• A complete set of known commands
is called an instruction list (or IL)
What makes a language?
•Languages, whether machine or natural,
encompass key elements:
▪Alphabet: Set of symbols forming words.
▪Lexis (Dictionary): Collection of words.
▪Syntax: Rules to create valid sentences.
▪Semantics: Rules for meaningful phrases.
Machine language vs. high-level language
•Machine Language
▪IL: The alphabet of machine language.
▪Basic symbols to command computers.
▪Simplest form of communication with
computers.
Machine language vs. high-level language
•High-Level Programming Languages:
▪Complex enough for humans, simpler
than natural language.
▪Use of symbols, words, and conventions
readable to humans.
Machine language vs. high-level language
•High-Level Programming Languages:
▪High-level language program: Source
code.
▪Program's content stored in a source file.
Compilation vs. Interpretation
• Computer programming is the act of composing
the selected programming language's elements
in the order that will cause the desired effect.
• Program needs to be translated into machine
language for execution.
• Computers can automate this translation
process, making the whole process fast and
efficient.
Compilation vs. Interpretation
Compilation:
• Source program translated into machine code
once.
• Resulting file (e.g., .exe) distributed for
execution.
• Utilizes a compiler or translator.
• Repeated compilation needed for source code
modifications.
Compilation vs. Interpretation
Interpretation:
• Source program translated each time it's run.
• Program called an interpreter transforms code on
the fly.
• Users require the interpreter to execute the code.
• Distribution of source code requires accompanying
interpreter.
What does the interpreter do?
• After writing a program, it exists as a
computer file.
• A computer program is essentially a
piece of text.
• Invoke the interpreter to process
your program.
• Interpreter sequentially reads,
checks, and executes code.
What does the interpreter do?
• Python is an interpreted language.
• If you want to program in Python, you'll need
the Python interpreter. You won't be able to run
your code without it. Fortunately, Python is free.
• Languages designed for interpretation often
termed "scripting languages."
• Source programs encoded using these languages
referred to as "scripts."
What is Python?
• Widely-used,
interpreted, objectoriented, high-level
programming language.
• comes from "Monty
Python's Flying Circus”,
a BBC television comedy
sketch series
Who created Python?
• Python's uniqueness: Created
by an individual.
• Guido van Rossum, born 1956,
Haarlem, Netherlands.
• first released on February 20,
1991.
• Python's global reach propelled
by collective efforts.
• Thousands of programmers,
testers, users, enthusiasts.
Why Python?
Where can we see Python in action?
• used extensively to implement complex Internet services
like:
▪ search engines
▪ cloud storage and tools
▪ social media and so on
• More and more everyday-use applications are being written in
Python.
• Scientists transition to Python for research and analysis
Python 2 vs. Python 3
• Python 2:
• Older version, development
intentionally stalled.
• Regular updates addressing bugs and
security.
• Active but not evolving language.
• Python 3:
• Current version, actively evolving.
• Creating new standards and
conventions.
• Independent language evolution.
Getting Started with Python
• Linux Users
Most Linux distributions come with Python pre-installed due to its integral role
in the system.
Check Python Installation: Open the terminal/console and type:
Press Enter and wait for the Python prompt.
Getting Started with Python
• Linux Users
Getting Started with Python
• If Python 3 is absent, refer to your Linux documentation to use your
package manager for installation:
• All non-Linux users can download a copy at
https://www.python.org/downloads/
Getting Started with Python
1. Visit the Python Download Page
• Open your web browser and go to: www.python.org/downloads
Getting Started with Python
2. Choose Your Python Version
• Since the website detects your OS, click on the Python 3
version offered. This will be the latest release
3. For Windows Users
• Download the .exe file.
• Run the downloaded file.
• Follow the installation steps.
• Important: Check the "Add Python 3.x to PATH" checkbox.
• Leave other settings as default for now.
Getting Started with Python
4. For macOS Users
• Python 2 might be preinstalled, but we'll work with
Python 3.
• Download the relevant .pkg file from the Python
site.
• Run the downloaded .pkg file.
• Follow the installation instructions.
Starting your work with Python
To start your work, you need the following
tools:
• Code Editor: support you in writing the code
• Console: Launch and control your code's
execution.
• Debugger: Step-by-step code execution for
thorough inspection.
Starting your work with Python
• Python 3 standard installation contains a very simple but extremely
useful application named IDLE (Integrated Development and Learning
Environment)