Topic 4 - Programming

Sub-procedures / Sub-Programs

When a problem is decomposed, you create smaller problems to solve. In programming, instead of having one function solve a whole problem, you can create smaller helper functions (sub-programs) to solve each of the smaller problems.

Identifier

Name of a variable, parameter, constant, user

Importance of sub-procedures

It helps create a modular approach to solving problems that are easier to debug and reason about.

Iteration

the process of repeating a series of instructions. (loop)

Conditional Statement

a statement that can be written in ifthen form and uses a boolean expression

Software Library

prewritten code, classes, procedures, etc that a programmer can use to add more functionality to his/her programs without having to rewrite the equivalent code.

Pre-Conditions

Assumptions that can be made and what must be true before the sub-procedure/function is called.

Post-Conditions

the effect a method has on its inputs (any unaffected/unlisted input should remain untouched), any generated exceptions, information about the return value, and effects on object state

Exceptions

an act or event that disrupts the anticipated flow of the program's execution

Concurrency

when two or more things happen at the same time. This is a term that is usually used with networking and/or multi-core processors. Different threads might make concurrent calls to websites or different processors.

Abstraction

Abstraction is the process of taking away or removing characteristics from something in order to reduce it to a set of essential characteristics.

Through the process of abstraction, a programmer hides all but the relevant data about an object in order to reduce complexity and increase efficiency.

The object or sub-program can then be called by name while preserving its functionality but hiding specific data/implementation.

Object-Oriented Programming

Programming that uses abstraction to represent real-world objects

Collection

A data structure that holds data and has methods used to iterate over that data

Object

an abstraction in code for a real-world object

Variable

a reference to a location in memory where data is stored

Constant

a variable that doesn't change

Operator

a character or characters that determine the action that is to be performed or considered

Arithmetic operators: +, -, \*, /, etc. \n Relational operators:

Array

In java, it is a static data structure with predetermined capacity.

Sequential Search

Searching through objects in a collection one by one, in order

Binary Search

Looking for an item in an already sorted list by eliminating large portions of the data on each comparison

Efficiency

the amount of computer resources used by a program uses

Correctness

whether a program can perform specified success criteria without errors

Reliability

whether an algorithm can consistently maintain efficiency and correctness

Flexibility

the amount of effort required to modify an algorithm for other purposes

Fundamental Computer Operations

add, compare, retrieve and store

Compound Computer Operations

the combination of fundamental operations into a more complex solution

Features of Programming Languages

Semantics: the process a language follows when executing a program's syntax

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Syntax: the keywords, operators and other valid constructs that make up a programming language.

Need for Programming Languages

Low level languages: used to perform operations on hardware, e.g. assembly language

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High level languages: used to give users easy-to-understand abstractions, which are then compiled into assembly language. e.g. python, java, javascript, etc.