[Data structure] basic concepts and terminology

Introduction to the first chapter

1.1 What is a data structure

The main content of data structure research:

The data structure is a subject of the computer operation object and the relation and operation between them in the programming problem of non-numerical computation.

1.2 Basic concepts and terminology

• Data: All the symbols that can be entered into the computer and processed by the computer are computer-operated

the general name of the elephant.

• Data element: A basic unit of data consisting of several data items, also called nodes, elements,

vertex or record.

• Data item: is the smallest unit of data that is inseparable, sometimes called a domain (field), that is, a data table

field.

• Data object: A collection of data elements of the same nature, which is a subset of the data, such as uppercase letters

The character data object is set C = {' A ', ' B ', ' C ',......, ' Z '}, the integer data object is set {0,±1,± 2, ...}.

• Data structure: Refers to a collection of elements that have one or more relationships with each other. Number

the relationship between elements is called a structure.

four basic data structures:

(1) Collection: Data elements "belong to one set".

(2) Linear structure: one to one, such as linear table, stack, queue.

(3) tree structure: A pair of multiple, such as a tree.

(4) Graphic structure: Multiple to multiple, as shown.

the form definition of the data structure:

data-structure = (d,s)

D: Finite set of data elements;

a finite set of relationships on S:d.

For example: In computer science, the plural is preferable to the following definition:

a complex number is a data structure

complex= (c,r)

where C is a set of two real numbers {C1,c2};r={p},p is a relationship defined on set C {<c1,c2>}, in which the ordered even <c1,c2> representation C1 is the real part of the complex, and C2 is the imaginary part of the complex number.

logical Structure of data: reflects only the logical relationships of data elements.

data Storage (physical) structure: the logical structure of the data is stored in the computer memory (or image).

element/node: A bit string used to represent the bits (bit) of a data element.

data field: A bit string used to represent the bits (bit) of a data item.

Example: (321) 10= (501) 8= (101000001) 2

a= (101) 8= (001000001) 2

The storage structure is divided into:

Sequential Storage structure: Represents the logical relationship between data elements by means of the relative position of elements in memory

Chained storage structure: Represents a logical relationship between data elements by means of pointers that indicate the storage address of an element