Computer Science | Sections 0-2

Computer

An electronic device that processes data, follows instructions, and produces results.

Input Devices

Devices such as keyboard and mouse that allow users to input data into a computer.

Output Devices

Devices such as monitor and printer that output data from a computer.

Central Processing Unit (CPU)

The primary component of a computer that performs most of the processing inside a computer.

Memory/Storage

Components like RAM and hard drive used to store data in a computer.

Computer Architecture

Describes how components communicate and interact with each other.

Bits

The basic unit of data in computing, represented as electrical signals (0s and 1s).

Unicode

A standard for encoding text from different languages using unique codes for each character.

Binary (Base 2)

A positional number system that uses two digits: 0 and 1.

Decimal (Base 10)

A positional number system that uses ten digits: 0-9.

Hexadecimal (Base 16)

A positional number system that uses sixteen digits: 0-9 and A-F.

int

Data type representing (e.g., 12, -5).

float

Data type representing numbers with decimals (e.g., 3.14, -0.5).

char

Data type representing a single character (e.g., 'a', 'Z').

Associativity

The order in which operators of the same precedence are evaluated.

Precedence

Determines which operator is evaluated first.

import

Loads an entire module in Python.

from … import …

Loads specific functions or classes from a module.

Dot Operator (. )

Accesses functions or attributes in a module.

Built-in Functions

Functions like type(), dir(), and help() that provide information about types and methods.

Turtle Functions

Drawing commands used in Turtle Graphics (e.g., forward(), left(), right()).

Positional vs Keyword Parameters

Positional parameters are passed in order; keyword parameters specify names.

Default Values

The value assigned to a function parameter when no corresponding argument is provided during the function call.

range Objects

Used to specify the sequence of numbers to iterate over in loops.

Sequential

Code runs line by line in order.

Iterative

Repeats code using loops (definite or indefinite).

Exception Handling

Manage errors and unexpected events that occur during program execution.

Boolean Operators

Operators such as and, or, not that combine or modify conditions.

elif

Checks extra conditions if previous ones are not True.

Initialization

Set starting value for the loop variable.

Mapping

The correspondence between strings of 0’s and 1’s and characters.

Machine Language

A mapping of instructions to particular strings that the CPU can process.

Hierarchy of Languages:

1) Machine Languages

2) Assembly Languages

3) High Level Languages

4) Very High Level Languages

Variables

Names for memory location.

Opcodes

Names for operations.

Compiler

Translates all code, then runs.

Interpreter

Translates code line by line (like a conversation).

Method/Function Calls

Jumps to a function, run its code, then returns.

Selection (if/else)

Make decisions and run different blocks of code based on conditions.

random

A package that is built to allow for psuedo-random number generation.

random.random()

Generates a random float in [0, 1).

random.randint(a,b)

Generates a random int in [a, b].

Flow of Control

Determining what code executes and in what order.

Iteration

Executes blocks of code zero or more times for loops.

While Loop

Initialization - pre-loop code to initialize variables used in a loop

Loop condition check - decide whether to keep iterating or not

Loop body - code which is being repeated