klips/cpp/datastructs/singlelist/singlelist.cpp

353 lines
10 KiB
C++

/*#############################################################################
## Author: Shaun Reed ##
## Legal: All Content (c) 2020 Shaun Reed, all rights reserved ##
## About: An example of a singly linked list ##
## ##
## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
##############################################################################
## singlelist.cpp
*/
#include "singlelist.h"
/******************************************************************************
* Constructors, Destructors, Operators
*****************************************************************************/
/** copy constructor
* @brief Construct a new SingleList::SingleList object from an existing one
*
* @param rhs SingleList object
*/
SingleList::SingleList(const SingleList& rhs)
{
Node *cp = rhs.head;
Node *tempHead;
if (cp == NULL) head = NULL;
else {
head = new Node(cp->data);
tempHead = head;
while (cp->next != NULL) {
cp = cp->next;
head->next = new Node(cp->data);
head = head->next;
}
head = tempHead;
}
}
/** operator=
* @brief Assign two SingleList objects equal using copy constr and class destr
* Pass the rhs by value to create local copy, swap its contents
* Destructor called on previous SingleList data at the end of this scope
*
* @param rhs SingleList object passed by value
* @return SingleList A deep copy of the rhs SingleList object
*/
SingleList SingleList::operator=(SingleList rhs)
{
if (this == &rhs) return *this;
std::swap(head, rhs.head);
return *this;
}
/** destructor
* @brief Destroy the SingleList::SingleList object
*/
SingleList::~SingleList()
{
makeEmpty();
}
/******************************************************************************
* Public Member Functions
*****************************************************************************/
/** insert
* @brief Inserts a value to the head of our linked list
*
* @param val The value to be inserted
*/
bool SingleList::insert(int val)
{
bool inserted = insert(val, head);
if (inserted)
std::cout << "[" << val << "] was inserted into the list\n";
else std::cout << "[" << val << "] could not be inserted into the list\n";
return inserted;
}
/** insert at
* @brief Inserts a value in the place of a given key
* Key Node found is moved to the newNode->next position
*
* @param key The value to search for to determine insert location
* @param val The value to be inserted into the list
*/
bool SingleList::insert(int val, int key)
{
bool inserted = insert(val, key, head);
if (inserted)
std::cout << "[" << val << "] was inserted into the list\n";
else std::cout << "[" << val << "] could not be inserted into the list\n";
return inserted;
}
/** remove
* @brief Removes a value in the list by calling a private member and handling output
*
* @param val Value to be removed from the list
* @return true If the value was removed from the list
* @return false If the value was not removed from the list
*/
bool SingleList::remove(int val)
{
bool removed = remove(val, head);
if (removed)
std::cout << "[" << val << "] was removed from the list\n";
else std::cout << "[" << val << "] could not be removed from the list\n";
return removed;
}
/** replace
* @brief Replaces a value in the list by calling a private member and handling output
*
* @param val Value to insert into the list
* @param key Value to be replaced within the list
* @return true If the key has been replaced in the list by val
* @return false If the key has not been replaced in the list by val
*/
bool SingleList::replace(int val, int key)
{
bool replaced = replace(val, key, head);
if (replaced)
std::cout << "[" << key << "] was replaced by [" << val << "] in the list\n";
else std::cout << "[" << key << "] could not be replaced by [" << val << "] in the list\n";
return replaced;
}
/** makeEmpty
* @brief Empty this SingleList object, deleting all associated Nodes
*/
void SingleList::makeEmpty()
{
Node *nextNode, *temp;
if (head == NULL) return;
nextNode = head->next;
delete head;
head = NULL;
while(nextNode != NULL) {
temp = nextNode;
nextNode = nextNode->next;
delete temp;
temp = NULL;
}
}
/** isEmpty
* @brief Determine if the SingleList is empty
*
* @return true If the SingleList::head is NULL
* @return false If the SingleList::head contains data
*/
bool SingleList::isEmpty() const
{
return head == NULL;
}
/** peek
* @brief returns the value at the SingleList::head
*
* @return int The value held at the Node pointed to by SingleList::head
*/
int SingleList::peek() const
{
if (!isEmpty())
std::cout << "[" << head->data << "] is at the top of our list\n";
else std::cout << "Nothing to peek, our list is empty...\n";
// If the list has data we return it, otherwise we return the smallest possible int (error)
return (!isEmpty()) ? head->data : INT32_MIN;
}
/** print
* @brief Output the data held by the SingleList object
* Calls to the private print()
*/
void SingleList::print() const
{
if(!isEmpty()) print(head);
else std::cout << "Nothing to print, our list is empty...\n";
}
/** find
* @brief Calls to the private member find() and handles return cases
*
* @param val The value to search for within our SingleList
* @return true If the value was found in this SingleList
* @return false If the value was not found in this SingleList
*/
bool SingleList::find(int val) const
{
Node *result = find(val, head);
if( result == NULL) {
std::cout << "[" << val << "] Was not found in our list\n";
return false;
}
std::cout << "[" << result->data << "] Was found in our list\n";
return true;
}
/******************************************************************************
* Private Member Functions
*****************************************************************************/
/** insert
* @brief Private member to handle inserting value into the list
*
* @param val Value to be inserted
* @param head The head of the list to insert the value into
* @return true If the value was inserted
* @return false If the value could not be inserted
*/
bool SingleList::insert(int val, Node *&head)
{
Node *newNode = new Node(val);
// If the list is not empty, update next pointer to head node
if (!isEmpty()) newNode->next = head;
// Always set head to our newNode
head = newNode;
return true;
}
/** insert at
* @brief Private member to handle inserting a value at a key within our list
*
* @param val Value to be inserted
* @param key Key value to search for within the list
* @param head Head node of the list to insert to
* @return true If the value was inserted
* @return false If the value was not inserted
*/
bool SingleList::insert(int val, int key, Node *&head)
{
Node *newNode = new Node(val);
if (isEmpty()) return false;
// Let insert() handle inserting at the head
else if (head->data == key) return insert(val);
Node *keyNode = findPrevious(key, head);
// If there was no keyNode found, the key does is not in our list
// Don't insert anything, return false and let caller decide whats next
if (keyNode == NULL) return false;
// Set the newNode to come BEFORE our keyNode
newNode->next = keyNode->next;
keyNode->next = newNode;
return true;
}
/** remove
* @brief Private member to remove values from the list
*
* @param val Value to be removed
* @param head Head of the list to remove the value from
* @return true If the value has been removed from the list
* @return false If the value has not been removed from the list
*/
bool SingleList::remove(int val, Node *&head)
{
if (head == NULL) return false;
else if (head->data == val) {
head = head->next;
return true;
}
Node *prevNode = findPrevious(val, head);
if (prevNode == NULL) return false;
Node *gtfo = prevNode->next;
prevNode->next = prevNode->next->next;
delete gtfo;
return true;
}
/** replace
* @brief Private member to replace values within the list
*
* @param val Value to insert into the list
* @param key Value to be replaced within the list
* @param head Head of the list to replace the value
* @return true If the key has been replaced by val within the list
* @return false If the key has not been replaced by val within the list
*/
bool SingleList::replace(int val, int key, Node *&head)
{
Node *replacee = find(key, head);
if (replacee == NULL) return false;
replacee->data = val;
return true;
}
/** find
* @brief Find and return a Node which contains the given value
*
* @param val The value to search for within our SingleList
* @param start The Node to start the search from
* @return SingleList::Node* A pointer to the Node containing the search value
*/
SingleList::Node* SingleList::find(int val, Node *start) const
{
// If given a NULL list, return NULL
// If given a head which contains the requested value, return the foundNode
if (start == NULL || start->data == val) return start;
Node *foundNode = start;
while (foundNode->next != NULL) {
foundNode = foundNode->next;
if (foundNode->data == val) return foundNode;
}
// If we have not yet returned a foundNode, the key is not in our list
return NULL;
}
/** findPrevious
* @brief Find and return the Node before a given value
*
* @param val The value to search for within our SingleList
* @param start The Node to start the search from
* @return SingleList::Node* A pointer to the Node previous to the given value
*/
SingleList::Node* SingleList::findPrevious(int val, Node *start) const
{
if (isEmpty()) return NULL;
else if (start->data == val) return start;
Node *temp = start;
while (temp->next != NULL) {
if (temp->next->data == val) return temp;
temp = temp->next;
}
return NULL;
}
/** print
* @brief Output the contents of a SingleList from the given Node to NULL
*
* @param start The Node to begin traversing output from
*/
void SingleList::print(Node *start) const
{
Node *temp = start;
std::cout << "List Contents: ";
while (temp != NULL) {
std::cout << temp->data << " | ";
temp = temp->next;
}
std::cout << std::endl;
}