Linked Lists in C, C++ and Java

8/6/2019 Linked Lists in C, C++ and Java

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Linked Lists in C, C++ and Java


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Doubly Linked List in C

Doublylinked list allows you to go through a

list in either direction.

The trick is to include an extra pointer in eachstructure

That stores the address ofthe previous

structure in addition to the pointer to the next

structure.

Compile and run the c program, 11.5


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How it works

The initial pointer declarations are now as follows:

struct horse *first = NULL; /* Pointer tofirst horse */

struct horse *current = NULL; /* Pointer to current horse */

struct horse *last = NULL; /* Pointer to previous horse */

struct horse /* Horse structure declaration */ {

int age;

int height;

char name[20];

char father[20];

char mother[20];CHAPTER 11 STRUCTURING DATA 429 struct horse *next; /* Pointer to next structure */

struct horse *previous; /* Pointer to previous structure */

};


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How it works

Two pointers:

One to point forward in the list, called next,

The other to point backward to the preceding structure, called previous.

for the pointer structure member previous. In the beginning ofthe input loop youhave the following

Other changes occur in the beginning ofthe loop if(first == NULL )

{

first = current; /* Set pointer tofirst horse */

current->previous = NULL;

}

else {

last->next = current; /* Set next address for previous horse */

current->previous = last; /* Previous address for current horse */

}


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How it works, C, doublylinked list

The other change is at the end ofthe input loop:

last = current; /* Save address oflasthorse */

This statement is added to allow the pointerprevious in the next structure tobe set to theappropriate value,

which is the current structure that yourerecording in the variable last.


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Templates: C++ Function Templates

Overloaded functions normally perform

similar or identicaloperations on different

types ofdata.

Ifthe operations are identicalfor each type,

they can be expressed more compactlyusing

function templates.

Allfunction-template definitions begin with

keyword template followed by a list of


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Allfunction-template definitions begin with

keyword template followed by a list of

template parameters to the function template

enclosed in angle brackets (< and >)

Each template parameter that represents a

type must be preceded by either ofthe

keywords class or typenane


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Template declaration example:

template< typename T >

or or

template< class ElementType >

template< typename BorderType, typenameFillType >


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Templates continued

The type template parameters are used to

specify types offunction arguments and

function return types

Keywords typename and class used to specify

function-template parameters actuallymean

"anyfundamental type or user-defined type.


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Templates continued

Load, compile and run 14_01.cpp

Note that templates saves youwriting the

same function logic for different data types


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Templates continued

void printArray( const int * const, int );

void printArray( const double * const, int );

void printArray( const char * const, int );


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Class Templates

Class templates are called parameterized

types, because they require one or more

typeparameters to specify how to customize a

"generic class" template


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Class Templates

To produce a varietyofclass-template

specializations youwrite onlyone

class-template definition. Each time anadditional class-template specialization is

needed, youuse a concise, simple notation,

and the compiler writes the source code for

the specialization you


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Class Templates

One Stack class template, for example, could

thus become the basis for creating many Stack

classes

"Stack ofdouble

"Stack ofint"

"Stack ofchar "Stack ofEmployee"


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Class Templates

Creating Class Template Stack< T>

Note the Stack class-template definition in Fig,

14,2, It looks like a conventional classdefinition, except that it's preceded by the

header (line 6)



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Class Templates

member-function definitions that appear

outside the class template definition each

begin with the header


Load compile run 14_03.cpp


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C++ Linked Lists

Linked lists are collections ofdata items

logically "lined up in a row"

insertions and removals are made anywherein a linked list.

A self-referential class contains a pointer

member that points to a class object ofthe

same class type.


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C++ Linked Lists

The programofFigs. 20.320.5 uses a List

class template

The primary Li st functions are insertAt- Front (lines 6274)

insertAtBack (lines 7789)

removeFromFront (lines 92110) removeFromBack (lines 113140)


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C++ Linked Lists

Function i sEmpty(lines 143147) is called a

predicate functionit does not alter the List;

rather, it determines whether the List is empty

(i.e., the pointer to the first node ofthe List is

NULL)


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Java Linked Lists

Alinked list is a linear collection (i.e., a

sequence) ofself-referential-class objects,

connected by reference linkshence, theterm linked list. Typically, a program

accesses a linked list via a reference to the first

node in the list.


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Java Linked Lists

The programofFigs. 17.317.5 uses an object

ofour List class tomanipulate a list of

miscellaneous objects. The program consists

offour classes

ListNode

List

EmptyListException

ListTest


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Java Linked Lists

Class ListNode (Fig. 17.3, lines 637) declares

package-access fields data and next-Node.

The data field is an Object reference, so it canrefer to anyobject.

ListNode member nextNode stores a reference

to the next ListNode object in the linked list

(or null ifthe node is the last one in the list).


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Java Linked Lists

Method isEmpty(lines 121124) is a

predicate method that determines whether

the list is empty(i.e., the reference to thefirstnode ofthe list is null)

Load Compile and run the code in Eclipse

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Linked Lists in C, C++ and Java