Merge pull request tanwanimohit#19 from Jacobite747/master

Add Simple Single Linked List Implementation (C++)

C++/LinkedList/linked_list.cpp

@@ -0,0 +1,144 @@
+#include <iostream>
+
+#include "linked_list.h"
+
+ListElement::ListElement()
+    : data_(0),
+      next_(nullptr) {
+}
+
+ListElement::ListElement(int data)
+    : data_(data),
+      next_(nullptr) {
+}
+
+List::List()
+    : head_(nullptr),
+      tail_(nullptr){
+}
+
+void List::AddElementEnd(int data) {
+    ListElement *elem = new ListElement;
+    elem->setData(data);
+    if (head_ == nullptr) {
+        head_ = elem;
+        tail_ = elem;
+    } else {
+        tail_->setNext(elem);
+        tail_ = elem;
+    }
+}
+
+void List::AddElementStart(int data) {
+    ListElement *elem = new ListElement;
+    elem->setData(data);
+    if (head_ == nullptr) {
+        head_ = elem;
+        tail_ = elem;
+    } else {
+        elem->setNext(head_);
+        head_ = elem;
+    }
+}
+
+void List::AddElementAt(int data, int pos) {
+    ListElement *elem = new ListElement;
+    elem->setData(data);
+    if (head_ == nullptr) {
+        head_ = elem;
+        tail_ = elem;
+    } else {
+        ListElement *current = new ListElement;
+        ListElement *pre = new ListElement;
+        elem->setData(data);
+        current = head_;
+        for (int i = 0; i < pos; i++) {
+            pre=current;
+            current = current->getNext();
+        }
+        pre->setNext(elem);
+        elem->setNext(current);
+    }
+}
+
+void List::DeleteFirst() {
+    if (head_ == nullptr) {
+        return;
+    } else if (head_->getNext() == nullptr) {
+        head_ = nullptr;
+        tail_ = nullptr;
+    } else {
+        ListElement *elem = new ListElement;
+        elem = head_;
+        head_ = head_->getNext();
+        delete elem;
+    }
+}
+
+void List::DeleteLast() {
+    if (head_ == nullptr) {
+        return;
+    } else if (head_->getNext() == nullptr) {
+        head_ = nullptr;
+        tail_ = nullptr;
+    } else {
+        ListElement *current = new ListElement;
+        ListElement *pre = new ListElement;
+        current = head_;
+        while(current->getNext() != nullptr) {
+            pre=current;
+            current=current->getNext();
+        }
+        tail_ = pre;
+        pre->setNext(nullptr);
+        delete current;
+    }
+}
+
+void List::DeleteAt(int pos) {
+    if (head_ == nullptr) {
+        return;
+    } else if (head_->getNext() == nullptr) {
+        head_ = nullptr;
+        tail_ = nullptr;
+    } else {
+        ListElement *current = new ListElement;
+        ListElement *pre = new ListElement;
+        current = head_;
+        for(int i = 1; i < pos; i++) {
+            pre = current;
+            current = current->getNext();
+        }
+        pre->setNext(current->getNext());
+    }
+}
+
+void List::DisplayList() {
+    if (head_ == nullptr) {
+        std::cout << "empty" << std::endl;
+    } else {
+        ListElement *temp;
+        temp = head_;
+        while(temp->getNext() != nullptr) {
+            std::cout << "(" << temp->getData() << ")-->";
+            temp = temp->getNext();
+        }
+        std::cout << "(" << temp->getData() << ")" << std::endl;
+    }
+}
+
+int List::Length() {
+    int count = 0;
+    if (head_ == nullptr) {
+        return 0;
+    } else {
+        ListElement *temp;
+        temp = head_;
+        while(temp->getNext() != nullptr) {
+            count += 1;
+            temp = temp->getNext();
+        }
+        count += 1;
+    }
+    return count;
+}

C++/LinkedList/linked_list.h

@@ -0,0 +1,41 @@
+#ifndef LINKEDLIST
+#define LINKEDLIST
+
+class ListElement {
+  public:
+    ListElement();
+    ListElement(int data);
+
+    void setData(int data) { data_ = data; }
+    int  getData() { return data_; }
+
+    void setNext(ListElement *next) { next_ = next; }
+    ListElement* getNext() { return next_; }
+
+  private:
+    int data_;
+    ListElement* next_;
+};
+
+
+class List {
+  public:
+    List();
+    void AddElementEnd(int data);
+    void AddElementStart(int data);
+    void AddElementAt(int data, int pos);
+
+    void DeleteLast();
+    void DeleteFirst();
+    void DeleteAt(int pos);
+
+    void DisplayList();
+    bool isEmpty() { return (head_ == nullptr); }
+    int Length();
+
+  private:
+    ListElement* head_;
+    ListElement* tail_;
+};
+
+#endif

C++/LinkedList/main.cpp

@@ -0,0 +1,18 @@
+#include <iostream>
+#include "linked_list.h"
+
+int main() {
+
+    List list;
+    list.AddElementEnd(2);
+    list.AddElementEnd(4);
+    list.AddElementEnd(5);
+    list.AddElementStart(1);
+    list.AddElementAt(3, 2);
+    list.DisplayList();
+
+    list.DeleteLast();
+    list.DeleteAt(2);
+    list.DeleteFirst();
+    list.DisplayList();
+}