Download 專業英文導讀 Chapter 11 End-Chapter Materials Key Terms Key

專業英文導讀
Chapter 11 End-Chapter Materials
Key Terms
Key Term
Definition
array
Definition: A fix-sized, sequenced collection
of elements of the same data type.
Example: An array is a sequenced collection
of elements, normally of the same data type,
although some programming languages
accept arrays in which elements are of
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different types.
data structure
Definition: The syntactical representation of
data organized to show the relationship
among the individual elements.
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Example: A data structure uses a collection of
related variables that can be accessed
individually or as a whole.
index
Definition: The address of an element in an
array.
Example: The index indicates the ordinal
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number of the element, counting from the
beginning of the array.
node
Definition: In a data structure, an element
that contains both data and structural
elements used to process the data structure.
Example: The elements in a linked list are
traditionally called nodes.
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one-dimensional array
Definition: An array with only one level of
indexing.
Example: The arrays discussed so far are
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known as one-dimensional arrays because
the data is organized linearly in only one
direction.
record
Definition: Information related to one entity.
Example: A record is a collection of related
elements, possibly of different types, having
a single name.
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two-dimensional array
Definition: An array with elements having
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two levels of indexing.
Example: Figure 11.5 shows a table, which is
commonly called a two-dimensional array.
column-major storage
Definition: A method of storing
two-dimensional arrays in which the
elements are stored column by column.
Example: A computer may store the array
using column-major storage, in which the
entire column is stored before the next
column.
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field
Definition: The smallest named unit of data
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that has meaning in describing information.
Example: A field is the smallest element of
named data that has meaning.
link
Definition: In a list structure, the field that
identifies the next element in the list.
Example: A linked list is a collection of data in
which each element contains the location of
the next element--that is, each element
contains two parts: data and link.
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multi-dimensional array
Definition: An array with elements having
more than one level of indexing.
Example: Multi-dimensional arrays--arrays
with more than two dimensions--are also
possible.
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null pointer
Definition: A pointer that points to nothing.
Example: The link in the last element
contains a null pointer, indicating the end of
the list.
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pointer
Definition: A constant or variable that
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contains an address that can be used to
access data stored elsewhere.
Example: The link is used to chain the data
together, and contains a pointer (an address)
that identifies the next element in the list.
row-major storage
Definition: A method of storing array
elements in memory in which the elements
are stored row by row.
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Example: Most computers use row-major
storage, in which an entire row of an array is
stored in memory before the next row.
linked list
Definition: A linear list structure in which the
ordering of the elements is determined by
link fields.
Example: A linked list is a collection of data in
which each element contains the location of
the next element-that is, each element
contains two part: data and link.
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searching
Definition: The process that examines a list to
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locate one or more elements containing a
designated value known as the search
argument.
Example: The searching algorithm for a linked
lists can only be sequential because the
nodes in a linked list have no specific names
that can be found using binary search.
Insertion
(insert operation)
Definition: An operation in a relational
database that inserts a tuple in a relation.
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Example: Before insertion into a list, we first
apply the searching algorithm.
deletion
(delete operation)
Definition: In a relational database, the
operation that deletes a tuple from the
relation.
Example: Deletion is simpler than insertion:
we have only two cases—deleting the first
node and deleting any other node.
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retrieval
Definition: The location and return of an
element in a list.
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Example: Retrieving means randomly
accessing a node for the purpose of copying
the data contained in the node.
traversal
Definition: An algorithm process in which
each element in a structure is processed one
and only once.
Example: To traverse the list, we need a
“walking” pointer, which is a pointer that
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moves from node to node as each element is
processed.
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Summary
A data structure uses a collection of related variables that can be accessed
individually or as a whole. In other words, a data structure represents a set of
data items that share a specific relationship. We discussed three data structures in
this chapter arrays, records, and linked lists.
An array is a sequenced collection of elements normally of the same data type.
We use indexes to refer to the elements of an array. In an array we have two
types of identifiers: the name of the array and the name of each individual
element.
Many applications require that data is stored in more than one dimension. One
common example is a table, which is an array that consists of rows and columns.
Two-dimensional arrays can stored in memory using either row-major or
column-major storage. The first is more common.
The common operations on arrays as a structure are searching, insertion, deletion,
retrieval, and traversal. An array is a suitable structure in applications number of
deletions and insertions is small but a lot of searching and retrieval operations
are required. An array is normally a static data structure and so is more suitable
when the number of data items is fixed.
A record is a collection of related elements, possibly of different types, having a
single name. Each element in a record is called a field. A held is the smallest
element of named data that has meaning in a record.
A linked list is a collection of data in which each element contains the location of
the next element; that is, each element contains two parts: data and link. The data
part holds the useful information: the data to be processed. The link is used to
chain the data together.
The same operations defined for an array can be applied to a linked list. A linked
list is a very efficient structure for data that will go through many insertions and
deletions. A linked list is a dynamic data structure in which the list can start with
no nodes and grow as new nodes are needed.
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