IB Computer Science Topic 4.3 - Introduction to Programming

Definition

Term

Nature of Programming Languages

Basic abilities of computer: Add, Compare, Retrieve, Store

Combinations of above. Example: Finding maximum of four numbers

Meaning of code/construction of programming language

"Grammar"/Rules of statement construction in programming language

Commands/Words with special meanings. Examples: import, int, static

Only language understood directly by computer, made of 1s and 0s => hard to write, debug, and maintain.

Unlike above, allows development of instructions and reference to address locations with mnemonics; program development is easier but each language supports only one specific computer system.

Translates above to machine code

Uses elements of natural language => easy to use, facilitates abstraction; program development is simpler, faster, and more understandable

Translates entire source program to object program only once, returning syntax errors if any. Examples: Java, C++

Unlike above, reads and translates one line of source program at a time. Examples: BASIC, Python

Handles code function on hardware platform.

.class file compiled from Java source code. Fed into interpreter afterwards.

Use of Programming Languages

Stores data element, which can be changed during execution, of program. Has name and type i.e. int age;

Like above but cannot be modified during execution. Example: final double PI = 3.14159;

Performs calculations i.e. "+", "-", "*", "/", "%"

Has data and actions/methods.

"=" / "=="

"≠" / "!="

">"

">="

"<"

"<="

"/" / "div"

"%" / "mod"

Visibility of variable, i.e. specific part(s) of algorithm, such as a loop, that can access and retrieve data of variable.

Consists of multiple elements - which may be duplicate - such as objects and values, and comes with necessary operations/methods, such as add and remove, that programmer can immediately use to manipulate data. Example: ArrayList

Allows programmers to save time by taking advantage of existing code developed either by themselves or other programmers.

Contains sequence of instructions that perform specific and predefined task. More than one of this may be contained in software libraries that can be used by programs. Three examples below.

Simply performs task or executes commands

May (get) or may not (void) return value

Small section of program customized by programmer to perform a particular task.