130 lines
4.1 KiB
C++
130 lines
4.1 KiB
C++
// Implementation file for the Student List class
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// Written by: Iurii Tatishchev
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// Reviewed, Debugged, & Modified by: Iurii Tatishchev
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// IDE: CLion
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#include <iostream> // For cout and NULL
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#include "StudentList.h"
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using namespace std;
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// **************************************************
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// Constructor
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// This function allocates and initializes a sentinel node
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// A sentinel (or dummy) node is an extra node added before the first data record.
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// This convention simplifies and accelerates some list-manipulation algorithms,
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// by making sure that all links can be safely dereferenced and that every list
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// (even one that contains no data elements) always has a "first" node.
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// **************************************************
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StudentList::StudentList() {
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head = new ListNode(Student()); // head points to the sentinel node
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head->setNext(NULL);
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count = 0;
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}
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// **************************************************
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// displayList shows the value
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// stored in each node of the linked list
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// pointed to by head.
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// **************************************************
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void StudentList::displayList() const {
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ListNode *pCur; // To move through the list
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// Position pCur: skip the head of the list.
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pCur = head->getNext();
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// While pCur points to a node, traverse the list.
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while (pCur)
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{
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// Display the value in this node.
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// cout << pCur->stu.getGpa() << " " << pCur->stu.getName() << endl;
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cout << pCur->getData().getGpa() << " " << pCur->getData().getName() << endl;
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// Move to the next node.
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pCur = pCur->getNext();
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}
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cout << endl;
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}
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// **************************************************
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// The insertNode function inserts a node with
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// dataIn copied to its stu member.
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// **************************************************
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void StudentList::insertNode(Student dataIn) {
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ListNode *newNode; // A new node
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ListNode *pCur; // To traverse the list
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ListNode *pPre; // The previous node
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// Allocate a new node and store num there.
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newNode = new ListNode(dataIn);
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// Initialize pointers
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pPre = head;
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pCur = head->getNext();
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// Find location: skip all nodes are alphabetically less than dataIn
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while (pCur != NULL && pCur->getData().getName() < dataIn.getName()) {
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pPre = pCur;
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pCur = pCur->getNext();
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}
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// Insert the new node between pPre and pCur
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pPre->setNext(newNode);
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newNode->setNext(pCur);
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// Update the counter
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count++;
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}
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// **************************************************
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// The deleteNode function searches for a node
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// with target as its value. The node, if found, is
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// deleted from the list and from memory.
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// **************************************************
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bool StudentList::deleteNode(string target) {
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ListNode *pCur; // To traverse the list
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ListNode *pPre; // To point to the previous node
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bool deleted = false;
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// Initialize pointers
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pPre = head;
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pCur = head->getNext();
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// Find node containing the target: Skip all nodes whose name is less than the target
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while (pCur != NULL && pCur->getData().getName() < target) {
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pPre = pCur;
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pCur = pCur->getNext();
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}
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// If found, delete the node
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if (pCur != NULL && pCur->getData().getName() == target) {
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pPre->setNext(pCur->getNext());
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delete pCur;
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deleted = true;
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count--;
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}
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return deleted;
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}
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// **************************************************
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// Destructor
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// This function deletes every node in the list.
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// **************************************************
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StudentList::~StudentList() {
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ListNode *pCur; // To traverse the list
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ListNode *pNext; // To point to the next node
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// Position nodePtr at the head of the list.
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pCur = head->getNext();
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// While pCur is not at the end of the list...
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while (pCur != NULL) {
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// Save a pointer to the next node.
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pNext = pCur->getNext();
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// Delete the current node
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delete pCur;
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// Position pCur at the next node.
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pCur = pNext;
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}
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delete head; // delete the sentinel node
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} |