List ADT

April 25, 2012

DefinitionA collection of contiguous elements or

itemsa1, a2, a3, …, an

n is the sizea2 precedes a3

a3 succeeds a2

DefinitionOperations

insertdeleteItem/eraseaccess

Humble Numbersvoid main(){

List<int> l;

srand((unsigned int)time(NULL));

for(int i=0; i<10; i++)

l.insert(rand()%50,rand()%10+1);

int count=0;

for(int i=1; i<=l.getSize(); i++){

int item = l.itemAt(i);

bool flag = true;

for(int cd=2; cd*cd<=item; cd++){

if(item%cd==0 && prime(cd) && cd>7){

flag = false;

break;

}

}

if(flag)

count++;

}

}

ImplementationArrayDynamic ArrayLinked-list

Array Implementation Array for storage Size

class List{

private:

int items[MAX];

int size;

public:

List();

bool append(int);

bool insertFront(int);

bool insert(int,int);

bool erase(int);

int itemAt(int);

};

Array Implementation

Append

10

Append

10 8

Append

10 8 -7

Append

bool List::append(int x){

if(size==MAX)

return false;

items[size++] = x;

return true;

}

Insert At Position 2

10 8 -7

Insert At Position 2

10 8 -7 -7

Insert At Position 2

10 8 8 -7

Insert At Position 2

10 23 8 -7

General Insert

bool List::insert(int x, int pos){

if(pos<1 || pos > size+1 || size==MAX)

return false;

for(int i=size; i>pos-1; i--)

items[i] = items[i-1];

items[pos-1] = x;

size++;

return true;

}

Insert at Front

10 23 8 -7

Insert at Front

10 23 8 -7 -7

Insert at Front

10 23 8 8 -7

Insert at Front

10 23 23 8 -7

Insert at Front

10 10 23 8 -7

Insert at Front

49 10 23 8 -7

Insert Front

bool List::insertFront(T x){

if(size==MAX)

return false;

for(int i=size; i>0; i--)

items[i] = items[i-1];

items[0] = x;

size++;

return true;

}

Delete Item at Position 2

49 10 23 8 -7

Delete Item at Position 2

49 23 23 8 -7

Delete Item at Position 2

49 23 8 8 -7

Delete Item at Position 2

49 23 8 -7 -7

DeleteItem/Erase

bool List::erase(int pos){

if(pos < 1 || pos > size)

return false;

for(int i=pos-1; i<size-1; i++)

items[i] = items[i+1];

size--;

return true;

}

Appending 13

49 23 8 -7 -7

Appending 13

49 23 8 -7 13

Accessing an Item

49 23 8 -7 13

itemAt

int List::itemAt(int pos){

return items[pos-1];

}

int List::itemAt(int pos){

if(pos<1 || pos>size)

throw “Invalid Position.”;

return items[pos-1];

}

AdvantagesRunning time

Access

DownsideStatic storageSolution

Dynamic Array

Dynamic Array Implementationclass template<T>;

class List{

private:

int *items;

int size;

void expand();

public:

List();

bool append(int);

bool insertFront(int);

bool insert(int,int);

bool erase(int);

int itemAt(int);

};

Constructor

List::List(){

items = new int[10];

size = 0;

}

List::~List(){

delete items;

}

Expandvoid List::expand(){

int *copy = new int[size];

for(int i=0; i<size; i++)

copy[i] = items[i];

delete items;

items = new int[size+10];

for(int i=0; i<size; i++)

items[i] = copy[i];

delete copy;

}

Linked List Implementation

9

Linked List Implementation

9 17

Linked List Implementation

9 1749

Linked List Implementation

-2 949 17

Memory Allocation (Heap)

0

32 17 NULL

64 9 32

96

128 49 182

150

182 -2 64

Linked List Implementation

class node{

public:

int item;

node *next;

node(int x){

item = x;

next = NULL;

}

};

Linked List Implementationclass List{

private:

node *head, *tail;

int size;

public:

List();

~List();

void append(int);

void insertFront(int);

bool insert(int,int);

int itemAt(int);

bool erase(int);

};

Constructor

List::List(){

head = tail = NULL;

size = 0;

}

Append

-2 949 17

23

Append

-2 949 17

23

Append

-2 949 17

23

Append

void List::append(int x);

node * n = new node(x);

tail->next = n;

tail = n;

size++;

}

Appendvoid List::append(int x);

node * n = new node(x);

if(size==0)

head = tail = n;

else{

tail->next = n;

tail = n;

}

size++;

}

insertFront

-2 949 17

23

103

insertFront

-2 949 17

23

103

insertFront

-2 949 17

23

103

insertFrontvoid List::insertFront(int x){

node *n = new node(x);

if(size==0)

head = tail = n;

else{

n->next = head;

head = n;

}

size++;

}

Insert at Position 6

-2 949 17

23

10367

Insert at Position 6

-2 949 17

23

10367

Insert at Position 6

-2 949 17

23

10367

Insert at Position 6

-2 949 17

23

10367

Insert at Position 6

-2 949 17

23

10367

Insert at Position 6

-2 949

23

17

10367

Insert at Position 6

-2 949

23

17

10367

Insert at Position 6

-2 949

23

17

10367

Insert at Position 6

-2 949

23

17

10367

Insert at Position 6

-2 949

23

17

10367

General Insertbool List::insert(int x, int pos){

if(pos < 1 || pos > size+1)

return false;

if(pos==1)

insertFront(x);

else

if(pos==size+1)

append(x);

else{

node * tmp = head;

for(int i=1; i<pos-1;i++)

tmp = tmp->next;

n->next = tmp->next;

tmp->next = n;

size++;

}

return true;

}

Delete Item at Position 3

-2 949 17

Delete Item at Position 3

-2 949 17

Delete Item at Position 3

-2 949 17

Delete Item at Position 3

-2 949 17

Delete Item at Position 3

-2 949 17

Delete Item at Position 3

-2 949 17

Delete Item at Position 3

-2 949 17

Delete Item at Position 3

-249 17

deleteItem/erasebool List::erase(int p){

if(p < 1 || p > size)

return false;

else{

node *del;

if(pos==1){

del = head;

head = head->next;

if(head==NULL)

tail = NULL;

}

else{

node * tmp = head;

for(int i=1; i<pos-1;i++)

tmp =tmp->next;

del = tmp->next;

tmp->next = del->next;

if(del==tail)

tail = tmp;

}

delete del; size--; return true;

}

}

itemAtint List::itemAt(int pos){

try{

node *tmp=head;

for(int i=1; i<pos; i++)

tmp = tmp->next;

return tmp->item;

}

catch(…){

throw “Invalid Position.”

}

}