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JAVA Software Development

Paradigm

 Advance OO Programming

BSCS Semester 6

MCS 3

Course nstructor! Ms" ram

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 #ava"util"$andom% Benc&mar's uses t&e #ava"util"$andom class

( a more controlled wa) to generate random

num*ers"

% f we set t&e same seed+ we get t&e same,random- se.uence"

$andom generator/ 0 new $andom12

$andom generator4 0 new $andom1seed2 long seed;

t&e seed is different

eac& time

int ' 0 generator"ne5tnt 1n2

dou*le 5 0 generator"ne5tDou*le 12

≤ k  7 n

≤  x  7 1

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 #ava"util"Arra)s

% Provides static met&ods for dealing wit&arra)s"

% 9or's for arra)s of num*ers+ Strings+ and

O*#ects"

% Met&ods!

int pos 0 Arra)s"binarySearch 1arr+ target2

 Arra)s"sort 1arr2

 Arra)s"fill 1arr+ value2 :: fills arr wit& a given value

String str 0 Arra)s"toString1arr2

 Arra)s"asList1arr2$eturns a representation of

arr  as a fi5ed8lengt& list

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 #ava"util"Collections

% Provides static met&ods for dealing wit& Arra)

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/=8>

Collection+ Iterator 

%  Collection interface represents an) collection"

%  An iterator is an o*#ect t&at &elps to traverset&e collection 1process all its elements in

se.uence2"

%  A collection supplies its own iterator1s2+1returned *) collection?s iterator  met&od2 t&e

traversal se.uence depends on t&e

collection"

@interface

Collection

@interface

Iterator 

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Collections

%   Collection+ Iterator 

%

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Overview

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Collection 

Met&ods  *oolean isHmpt) 12

  int siIe 12

  *oolean contains 1O*#ect o*#2  *oolean add 1H o*#2

  *oolean remove 1H o*#2

  terator7H iterator  12

  :: """ ot&er met&ods

Supplies an

iterator for t&is

collection

@interface

Collection

@interface

Iterator 

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Iterator 

Met&ods

  *oolean &asEe5t 12  H ne5t 12

  void remove 12

@interface

Collection

@interface

Iterator 

9&at?s ,ne5t- isdetermined *) a

particular collection

$emoves t&e last

visited element

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List 7E  

Met&ods

@interface

Collection

@interface

Iterator 

@interface

ListIterator 

@interface

List 

  :: All Collection7E  met&ods+ plus!

  H get 1int i2  H set 1int i+ H o*#2

  void add 1int i+ H o*#2

  H remove 1int i2

  int inde5Of  1O*#ect o*#2 

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ListIterator 7E  

Met&ods

@interface

Collection

@interface

Iterator 

@interface

ListIterator 

@interface

List 

  :: &e t&ree Iterator 7E  met&ods+ plus!  int ne5tnde5 12

  *oolean &asPrevious 12

  H previous 12

  int previousnde5 12

  void add 1H o*#2

  void set 1H o*#2

Can traverse t&e

list *ac'ward

Can add elements to t&e list 1inserts

after t&e last visited element2

Can c&ange elements 1c&anges

t&e last visited element2

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 Arra)

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/=8/>

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  Arra)

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 #ava"util"Arra)

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 Arra)+ Arra)

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 Arra)

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/4844

 Arra)

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/4843

 Arra)

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/484;

 Arra)

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/484>

 Arra)

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/4846

 Arra)

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/484F

 Arra)

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,Kor Hac&-

% 9or's *ot& wit& standard arra)s and Arra)

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,Kor Hac&-

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,Kor Hac&-

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/= 3/

terator VS ,Kor Hac&-