Lecture 1

Welcome to MUH101

Burkay Genç, Ahmet Selman Bozkır, and Selma Dilek

20/02/2024

Today

  • course Info
  • what is computation
  • python basics
  • mathematical operations
  • python variables and types

Course Info

  • Subject : Learn Python a programming language
  • Classes :
    • All classes are face-to-face
    • All off-class communication will be on Hacettepe University Digital Learning Platform (HADİ)
      • hadi website
      • You have to follow hadi daily for new announcements

Course Info

  • Grading
    • 60%: Midterm (2x)
      • Midterms format will be announced during the semester
    • 40%: Final Exam (1x)

Course Info

  • You are strictly forbidden to cooperate on exams
  • You are strictly forbidden to search for answers on the Internet
  • You are strictly forbidden to copy/paste materials from the Internet

COURSE POLICIES

  • Cooperation
    • you may cooperate with your friends to understand the course material
    • all exam work needs to be individual
      • cheaters will be harshly penalized -> -100, F3, disciplinary committee

FAST PACED COURSE

  • Position yourself to succeed!
    • do practice early
    • do not skip lectures
  • New to programming? PRACTICE. PRACTICE? PRACTICE!
    • can’t passively absorb programming as a skill
    • download code before lecture and follow along
    • don’t be afraid to try out Python commands!

TOPICS

  • represent knowledge with data structures
  • iteration and recursion as computational metaphors
  • abstraction of procedures and data types
  • organize and modularize systems using object classes and methods
  • [maybe] different classes of algorithms, searching and sorting
  • [maybe] complexity of algorithms

WHERE TO GET PYTHON

PYTHON IDE

  • What is an IDE?
    • An Integrated Development Environment allows you to write programs in a programming language and provides extra tools to help the process
      • Syntax highlighting
      • Code completion
      • Bracket completion/matching
      • Debugging
      • Profiling
      • more…
  • PyCharm is a very powerful and popular IDE for Python
  • IDLE comes built-in with any Python distribution
  • Eric, Spyder, Eclipse+PyDev
  • Sublime Text, VS Code, Atom, etc. are generic editors that can be extended with Python capabilities

WHAT DOES A COMPUTER DO

  • Fundamentally:
    • performs calculations
      a billion calculations per second!
    • remembers results
      100s of gigabytes of storage!
  • What kinds of calculations?
    • built-in to the language
    • ones that you define as the programmer
  • computers only know what you tell them

TYPES OF KNOWLEDGE

  • declarative knowledge is statements of fact.

    • someone will win a Trophy before class ends
  • imperative knowledge is a recipe or “how-to”.

    1. Students sign up for lottery
    2. Burkay opens his IDE
    3. Burkay chooses a random number between 1st and nth responder
    4. Burkay finds the number in the responders sheet. Winner!

A NUMERICAL EXAMPLE

  • square root of a number x is y such that yy=x

  • recipe for deducing square root of a number x

    1. Start with a guess, g
    2. If gg is close enough to x, stop and say g is the answer
    3. Otherwise make a new guess by averaging g and x/g
    4. Using the new guess, repeat process until close enough
g gg x/g (g+x/g)/2
3 9 16/3 4.17
4.17 17.36 3.837 4.0035
4.0035 16.0277 3.997 4.000002

WHAT IS A RECIPE

  1. sequence of simple steps
  2. flow of control process that specifies when each step is executed
  3. a means of determining when to stop

1 + 2 + 3 = an algorithm!

COMPUTERS ARE MACHINES

  • how to capture a recipe in a mechanical process
  • fixed program computer
    • calculator
  • stored program computer
    • machine stores and executes instructions

BASIC MACHINE ARCHITECTURE

Basic machine architecture

STORED PROGRAM COMPUTER

  • sequence of instructions stored inside computer
    • built from predefined set of primitive instructions
      • arithmetic and logic
      • simple tests
      • moving data
  • special program (interpreter) executes each instruction in order
    • use tests to change flow of control through sequence
    • stop when done

BASIC PRIMITIVES

  • Turing showed that you can compute anything using 6 primitives
  • modern programming languages have more convenient set of primitives
  • we can also create new primitives
  • anything computable in one language is computable in any other programming language
    • Python == Java == C == Pascal == C++ == C#
    • They only differ in ease of doing something

CREATING RECIPES

  • a programming language provides a set of primitive constructs
    • 2, 4.8, ‘a’, “burkay”, TRUE, +, -, *, …
  • expressions are complex but legal combinations of primitives in a programming language
    • 2 + 4.7
    • TRUE && FALSE
    • 3.0 + 2 / 5.4
  • expressions and computations have values and meanings in a programming language

ASPECTS OF LANGUAGES

  • primitive constructs
    • English: words
    • programming language: numbers, strings, simple operators