school/cs235/lab03/sm/ll.cc

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2016-04-06 20:46:10 -07:00
#include "ll.h"
ll::ll(): _size(0), head(NULL), tail(NULL) {
}
ll::~ll() {
clear();
}
void ll::insertHead(int value) {
if(value < 0 or find(value)) {
return;
}
if(head == NULL) {
assert(tail == NULL);
assert(_size == 0);
head = new node(value);
tail = head;
}
else {
node * tmp = head;
head = new node(value);
head->next = tmp;
}
_size++;
}
void ll::insertTail(int value) {
if(value < 0 or find(value)) {
return;
}
if(tail == NULL) {
assert(head == NULL);
assert(_size == 0);
tail = new node(value);
head = tail;
}
else {
node * tmp = tail;
tmp->next = new node(value);
tail = tmp->next;
}
_size++;
}
void ll::insertAfter(int value, int insertionNode) {
if(value < 0 or find(value)) {
return;
}
node * inlist = find(insertionNode);
if(not inlist) {
return;
}
node * toinsert = new node(value);
if(inlist == tail) {
tail = toinsert;
}
toinsert->next = inlist->next;
inlist->next = toinsert;
_size++;
}
void ll::remove(int value) {
if(not find(value)) {
// should deal with empty list, and not found
return;
}
else if(head == tail) {
delete head;
head = tail = NULL;
_size--;
}
else {
node * cur = head;
if(head->value == value) {
head = head->next;
delete cur;
_size--;
}
else {
while(cur) {
if(cur->next == NULL) {
// removing end ...
break;
}
if(cur->next->value == value) {
node * to_remove = cur->next;
if(to_remove == tail) {
tail = cur;
}
cur->next = to_remove->next;
delete to_remove;
_size--;
}
cur = cur->next;
}
}
}
}
void ll::clear() {
node * tmp = head;
while(head) {
tmp = head;
head = head->next;
delete tmp;
_size--;
}
head = tail = NULL;
assert(_size == 0);
}
int ll::at(int index) {
if (index >= _size or index < 0) {
return -1;
}
node * tmp = head;
for(int i = 0; i < index; i++) {
tmp = tmp->next;
}
if(tmp == NULL) {
return -1;
}
else {
return tmp->value;
}
}
int ll::size() {
return _size;
}
node * ll::find(int value) {
node * tmp = head;
while(tmp) {
if(tmp->value == value) {
return tmp;
}
tmp = tmp->next;
}
return NULL;
}
ostream & operator<<(ostream & os, const node & n) {
os << n.value;
return os;
}
ostream & operator<<(ostream & os, const ll & l) {
os << "ll {(" << l._size << ") ";
node * cur = l.head;
while (cur) {
os << *cur << ", ";
cur = cur->next;
}
os << "}";
return os;
}