What is Code?

Main ideas / concepts conveyed

• Code as symbol-based information

  • By definition, code is a way to convey useful information using symbols.
  • Symbols become meaningful only when they are read in a predefined way.
  • Computer-readable code is called a program or software.

• Code exists beyond computers

  • Color codes (e.g., traffic lights):
    • Red = stop
    • Yellow = slow down
    • Green = go
  • Genetic code (DNA) as biological instructions:
    • DNA encodes instructions to build proteins.
    • DNA is read such that sets of three chemicals correspond to amino acids.
    • There are start and stop triplets that mark where instruction begins and ends.
  • Morse code:
    • Dot (.) = short signal (beep/light)
    • Dash (-) = long signal (beep/light)
    • Letters are encoded using dot/dash patterns (example given: SOS).
  • Natural language as code:
    • Speaking/writing English encodes intended meaning.
    • Listeners decode the language to extract the message.

• Programming languages as the “translation” layer for computers

  • Computers can’t understand natural language (English/Spanish).
  • To give computers instructions, you use a programming language.
  • Examples mentioned: JavaScript, Python, C, C++.
  • Programming languages share common concepts:
    • Variables, loops, functions
  • Learning one programming language helps with learning others because they are conceptually similar.

• Abstraction layers: what programmers write vs. what computers execute

  • Programming is done at a high level of abstraction (simpler instructions).
  • Under the hood, the computer translates that into:
    • Assembly code (more detailed commands)
    • Machine code (zeros and ones, the lowest level)
  • Example idea:
    • Writing something like “move” is simple for a programmer, but the computer converts it into low-level instructions that ultimately drive hardware behavior (e.g., moving a character across the screen).

• Programs consist of input, processing, and output

  • Input
    • Keyboard presses and mouse clicks produce numbers sent to the computer.
  • Processing
    • The program processes those numbers to decide what actions to take.
  • Output
    • The program produces more numbers representing what to display or play (e.g., colors, sounds).
  • Overall principle:
    • At the base level, everything is represented as numbers, ultimately encoded as zeros and ones.

Methodology / instruction-like structure (process described)

• How code gets from intention to computer action (conceptual pipeline)

  • Write a program in a high-level programming language (your intent expressed with big ideas like move, turn, etc.).
  • When running, a compiler translates the program into:
    • Machine code (zeros and ones) that the CPU can execute.
  • The executed machine code drives actions corresponding to the program’s logic.

• How computation works at runtime

  • Input: user actions (keyboard/mouse) generate encoded numbers.
  • Processing: the program interprets/processes the numbers to determine the next steps.
  • Output: the program generates encoded output numbers that instruct the computer to display/play something.

Speakers or sources featured

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