Chapter 7 - Data Structures and Abstract Data Types

Static Data Structure

*Fixed in size* and cannot increase in size or free up memory while the program is running. Eg. the size of an array has to be decared in advance.

Data Structure

*Implementation* of an Abstract Data Type. A collection of elementary data types such as *integer*, *real*, *Boolean* etc.

Queue

A *First In, First Out* (FIFO) data structure. The first item added is the first item removed.

Stack

A *Last In, First Out* (LIFO) data structure. The last item added is the first item removed.

Array

A *finite*, *ordered set of elements* of the same type. Can work with multiple dimensions. Arrays are *static data structures*

Dynamic Data Structure

A collection of data in memory that has the ability to *grow or shrink in size*. This is done with the *aid of the heap*.

Abstract Data Type (ADT)

A data type whose properties & operations are specified independently of any particular programming language. This results in *data abstraction*.

Heap

A portion of memory from which space is automatially *allocated or de-allocated* as required.

Binary File

Can contain records with *different types of field*, occupying a *different number of bytes* etc. Data is stored as a *string of 1s and 0s* & the format has to be known by the program.

Files

Consists of a number of *records*. A record contains a number of *fields*, each holding an *item of data*.

Text File

Contains *human readable characters* (decoded from binary).