klips/cpp/datastructs/stacklist/stacklist.cpp

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2020-06-11 22:32:53 +00:00
/*#############################################################################
## Author: Shaun Reed ##
## Legal: All Content (c) 2020 Shaun Reed, all rights reserved ##
## About: An example of a stack implementation using linked lists ##
## ##
## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
##############################################################################
## stacklist.cpp
*/
#include "stacklist.h"
/******************************************************************************
* Constructors, Destructors, Operators
*****************************************************************************/
/** copy constructor
* @brief Construct a new StackList::StackList object from an existing one
* Creates a new deep copy of a given StackList
*
* @param rhs StackList object
*/
StackList::StackList(const StackList& rhs)
{
Node *cp = rhs.head;
Node *tempHead;
// If we are copying from an empty stack, create a new StackList with a NULL head
if (cp == NULL) head = NULL;
else {
// If the stack has data, initialize a new stack with the head data
head = new Node(cp->data);
// Keep a temporary head node so we can return to it later
tempHead = head;
while (cp->next != NULL) {
// Until we hit an end, create new nodes with the next node data
cp = cp->next;
head->next = new Node(cp->data);
head = head->next;
}
head = tempHead;
}
}
/** operator=
* @brief Assign two StackList objects equal using copy constr and class destr
* Pass the rhs by value to create local copy, swap its contents
* Destructor called on previous StackList data at the end of this scope
*
* @param rhs StackList object passed by value
* @return StackList A deep copy of the rhs StackList object
*/
StackList StackList::operator=(StackList rhs)
{
if (this == &rhs) return *this;
// Swap the pointers, moving the previous head data to the local variable rhs
std::swap(head, rhs.head);
return *this;
}
/** destructor
* @brief Destroy the StackList::StackList object
*/
StackList::~StackList()
{
makeEmpty(head);
}
/******************************************************************************
* Public Member Functions
*****************************************************************************/
/** push
* @brief Push a value to the head of our linked list
*
* @param val The value to be inserted
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*/
bool StackList::push(int val)
{
bool inserted = push(val, head);
if (inserted)
std::cout << "[" << val << "] was inserted into the stack\n";
else std::cout << "[" << val << "] could not be inserted into the stack\n";
return inserted;
}
/** pop
* @brief returns the value at the StackList::head
*
* @return int The value held at the Node pointed to by StackList::head
*/
int StackList::pop()
{
if (!isEmpty())
std::cout << "[" << pop(head) << "] has been popped from our stack\n";
else std::cout << "Nothing to pop, our stack is empty...\n";
// If the stack has data we return it, otherwise we return the smallest possible int (error)
return (!isEmpty()) ? head->data : INT32_MIN;
}
/** top
* @brief returns the value at the StackList::head
*
* @return int The value held at the Node pointed to by StackList::head
*/
int StackList::top() const
{
if (!isEmpty())
std::cout << "[" << head->data << "] is at the top of our stack\n";
else std::cout << "Our stack is empty...\n";
// If the stack has data we return it, otherwise we return the smallest possible int (error)
return (!isEmpty()) ? head->data : INT32_MIN;
}
/** makeEmpty
* @brief Empty this StackList object, deleting all associated Nodes
*/
void StackList::makeEmpty()
{
Node *nextNode, *temp;
if (head == NULL) std::cout << "Our stack is empty...\n";
else {
nextNode = head->next;
delete head;
head = NULL;
while(nextNode != NULL) {
temp = nextNode;
nextNode = nextNode->next;
delete temp;
temp = NULL;
}
}
}
/** isEmpty
* @brief Determine if the StackList is empty
*
* @return true If the StackList::head is NULL
* @return false If the StackList::head contains data
*/
bool StackList::isEmpty() const
{
return head == NULL;
}
/** print
* @brief Output the data held by the StackList object
* Calls to the private print()
*/
void StackList::print() const
{
if(!isEmpty()) print(head);
else std::cout << "Nothing to print, our stack is empty...\n";
}
/******************************************************************************
* Private Member Functions
*****************************************************************************/
/** push
* @brief Private member to handle inserting value into the stack
*
* @param val Value to be inserted
* @param head The head of the stack to push the value into
* @return true If the value was inserted
* @return false If the value could not be inserted
*/
bool StackList::push(int val, Node *&head)
{
Node *newNode = new Node(val);
// If the stack is not empty, update next pointer to head node
if (!isEmpty()) newNode->next = head;
// Always set head to our newNode
head = newNode;
return true;
}
/** pop
* @brief Private member to handle removing the head node from the stack
*
* @param head The head node of the stack
* @return The last known value held at the head node before removal
*/
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int StackList::pop(Node *&head)
{
// We already know the stack is not empty from public pop()
Node *temp = head;
int data = temp->data;
head = head->next;
delete temp;
return data;
}
/** print
* @brief Output the contents of a StackList from the given Node to NULL
*
* @param start The Node to begin traversing output from
*/
void StackList::print(Node *start) const
{
Node *temp = start;
std::cout << "Stack Contents: ";
while (temp != NULL) {
std::cout << temp->data << " | ";
temp = temp->next;
}
std::cout << std::endl;
}
/** makeEmpty
* @brief Private member to empty this StackList object, deleting all associated Nodes
* Does not print any output. Avoids destructors printing to cout
*
* @param head The head of the stack to be deleted
*
*/
void StackList::makeEmpty(Node *&head)
{
Node *nextNode, *temp;
if (head == NULL) return;
else {
nextNode = head->next;
delete head;
head = NULL;
while(nextNode != NULL) {
temp = nextNode;
nextNode = nextNode->next;
delete temp;
temp = NULL;
}
}
}