High Level Languages

A2 Computing F453 Advanced Computing Theory High Level Languages

Definitions | Tiju Thomas

ALGORITHM

A set of instructions used to complete a particular task.



UNIFIED MODELLING LANGUAGE

A descriptive diagrammatic representation to describe the stages

required to produce effective Object Orientated programs.

Standard form of presenting information.

Allows systems analysts, programmers and clients to communicate.

Makes system maintenance easier when modifying a system.



CLASS DIAGRAM

A class is an entity of a given system that provides an encapsulation

of the functionality of a given entity.

Block split up into three, containing class name, attributes and

methods/operations.



OBJECT DIAGRAM

An object diagram consists of the first 2 rows of a Class diagram

The first row would contain the objects name.

The second row would contain the values for the objects attributes.



USE CASE DIAGRAM

Actors.

Interactions between processes.



SEQUENCE DIAGRAM

How the objects in the class interact with each other.

Dotted line = lifeline which shows the passage of time vertically

from top to bottom.

When the lines become thick, the methods have been activated.



COMMUNICATION DIAGRAM

How different objects combine to pursue a common purpose.



CLASS

Contains the attributes and methods.

A template for objects, each object of that class will contain its

attributes and methods.

Object Orientated.

Allows for Data Encapsulation.



OBJECT

An instance of a class.

A real-world entity.

Holds methods and attributes.



METHOD

A way of interacting with objects.



ATTRIBUTE

Characteristics of the items within a class.



INHERITANCE

The process of passing on methods and attributes from a super

class to a sub class while allowing the sub class to have its own

attributes and methods.

This can help to reduce errors as the attributes and methods do not

have to be written each time they are needed in the diagram.



CONSTRUCTOR

A method with the same name as the class which is executed when

an instance of a class is created.



POLYMORPHISM

This is when multiple methods have the same name but have

different parameter lists. Eg. Constructor.



ENCAPSULATION

The attributes and methods are hidden from anything outside the

class.

Objects can only access the data by using the methods provided.

An object cannot manipulate the date directly.



PROCEDURAL LANGUAGE

3rd Generation.

Step by step instructions to solve a problem.



DECLARATIVE LANGUAGE

4th Generation.

States what to achieve without giving detailed steps by declaring

facts and rules.

Fact

o Predicate which may have arguments.

o Something that is always (unconditionally) true.

Goal

o A query to be solved.

Backtracking

o After finding a solution for a goal, or if a goal fails,

o Going back to an earlier point to take an alternative route.

Instantiation

o Giving a variable a in a statement a value.

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