From a3cc673c86b7dc6e6fbf9920ac4235384a31599e Mon Sep 17 00:00:00 2001
From: Iurii Tatishchev <itatishch@gmail.com>
Date: Sun, 28 Apr 2024 12:25:34 -0700
Subject: [PATCH] 6.20 Lab: Doubly-Linked List (Delete)

---
 04-dl-lists/StudentList.cpp | 27 +++++++++++++++++++++++++++
 04-dl-lists/StudentList.h   |  5 ++---
 04-dl-lists/main.cpp        | 33 +++++++++++++++------------------
 3 files changed, 44 insertions(+), 21 deletions(-)

diff --git a/04-dl-lists/StudentList.cpp b/04-dl-lists/StudentList.cpp
index 5077c2e..912d5db 100644
--- a/04-dl-lists/StudentList.cpp
+++ b/04-dl-lists/StudentList.cpp
@@ -103,6 +103,33 @@ void StudentList::insertNode(Student dataIn) {
     count++;
 }
 
+// **************************************************
+// The deleteNode function deletes a node with
+// the same key as its paramenter, if found
+// **************************************************
+bool StudentList::deleteNode(string target) {
+    ListNode *pCur;     // To traverse the list
+    bool success = false;
+
+    pCur = head->forw;
+    while (pCur != head && pCur->stu.name < target) {
+        pCur = pCur->forw;
+    }
+
+    if (pCur != head && pCur->stu.name == target) {
+        ListNode *pPrev = pCur->back;
+        ListNode *pNext = pCur->forw;
+        pPrev->forw = pNext;
+        pNext->back = pPrev;
+        delete pCur;
+        success = true;
+        count--;
+    }
+
+    return success;
+}
+
+
 // **************************************************
 // Destructor                                      *
 // This function deletes every node in the list.   *
diff --git a/04-dl-lists/StudentList.h b/04-dl-lists/StudentList.h
index 5a6d8b6..0782110 100644
--- a/04-dl-lists/StudentList.h
+++ b/04-dl-lists/StudentList.h
@@ -7,8 +7,6 @@
 #ifndef STUDENTLIST_H
 #define STUDENTLIST_H
 
-#include <string>
-
 struct Student {
     double gpa;
     std::string name;
@@ -36,7 +34,8 @@ public:
 
     void insertNode(Student);
 
-    //bool deleteNode(double);
+    bool deleteNode(std::string);
+
     //void searchList() const;
     void displayListForw() const;
 
diff --git a/04-dl-lists/main.cpp b/04-dl-lists/main.cpp
index 0caf983..00d78bd 100644
--- a/04-dl-lists/main.cpp
+++ b/04-dl-lists/main.cpp
@@ -1,17 +1,17 @@
 /*
- CIS 22C
+CIS 22C: Sorted Circular Doubly-Linked List with Sentinel Node
 
- Sorted Circular Doubly-Linked List with Sentinel Node
-
- This program:
-- Creates a sorted linked list (student name and gpa) . The list is sorted in ascending order by name.
+This program:
+- Creates a sorted linked list (student name and gpa). The list is sorted in ascending order by name.
 - Displays the list forwards(A to Z)
+- Deletes nodes from the list
 - Displays the list backwards(Z to A)
 
- Requirements: Finish writing the following three functions:
-- default constructor
-- insertNode()
-- displayListBack()
+Your task is to finish writing the following three functions:
+- default constructor (reuse code from your previous Lab)
+- insertNode()  (reuse code from your previous Lab)
+- displayListBack()  (reuse code from your previous Lab)
+- deleteNode()
 
  Written by: Iurii Tatishchev
  Reviewed by: Iurii Tatishchev
@@ -33,15 +33,14 @@ int main() {
 
     buildList(list); // insert data into the list
     cout << "There are " << list.getCount() << " elements in the list." << endl;
-
     string answer;
-    cout << "Insert [Y/N]? ";
+    cout << "Delete [Y/N]? ";
     getline(cin, answer);
     if (answer == "Y" || answer == "y") {
-        Student s;
-        cout << "Enter gpa then enter name:" << endl;
-        cin >> s.gpa >> s.name;
-        list.insertNode(s);
+        string targetName;
+        cout << "Enter name to be removed from the list:" << endl;
+        getline(cin, targetName);
+        cout << targetName << (list.deleteNode(targetName) ? " - deleted!" : " - not found!") << endl;
         cout << "There are " << list.getCount() << " elements in the list." << endl;
     }
     cout << endl;
@@ -69,6 +68,4 @@ void buildList(StudentList &list) {
         getline(cin, line);
     }
 
-}
-
-
+}
\ No newline at end of file