Doubly-linked-list.cpp

Doubly-linked-list.cpp

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+// Inserting sorted elements in doubly linked list
+#include <bits/stdc++.h> 
+
+using namespace std; 
+
+// Node of a doubly linked list 
+struct Node { 
+    int data; 
+    struct Node* prev, *next; 
+}; 
+
+// function to create and return a new node 
+// of a doubly linked list 
+struct Node* getNode(int data) 
+{ 
+    // allocate node 
+    struct Node* newNode =  
+        (struct Node*)malloc(sizeof(struct Node)); 
+
+    // put in the data 
+    newNode->data = data; 
+    newNode->prev = newNode->next = NULL; 
+    return newNode; 
+} 
+
+// function to insert a new node in sorted way in 
+// a sorted doubly linked list 
+void sortedInsert(struct Node** head_ref, struct Node* newNode) 
+{ 
+    struct Node* current; 
+
+    // if list is empty 
+    if (*head_ref == NULL) 
+        *head_ref = newNode; 
+
+    // if the node is to be inserted at the beginning 
+    // of the doubly linked list 
+    else if ((*head_ref)->data >= newNode->data) { 
+        newNode->next = *head_ref; 
+        newNode->next->prev = newNode; 
+        *head_ref = newNode; 
+    } 
+
+    else { 
+        current = *head_ref; 
+
+        // locate the node after which the new node 
+        // is to be inserted 
+        while (current->next != NULL &&  
+               current->next->data < newNode->data) 
+            current = current->next; 
+
+        /* Make the appropriate links */
+        newNode->next = current->next; 
+
+        // if the new node is not inserted 
+        // at the end of the list 
+        if (current->next != NULL) 
+            newNode->next->prev = newNode; 
+
+        current->next = newNode; 
+        newNode->prev = current; 
+    } 
+} 
+
+// function to print the doubly linked list 
+void printList(struct Node* head) 
+{ 
+    while (head != NULL) { 
+        cout << head->data << " "; 
+        head = head->next; 
+    } 
+} 
+
+// Driver program to test above 
+int main() 
+{ 
+    /* start with the empty doubly linked list */
+    struct Node* head = NULL; 
+
+    // insert the following nodes in sorted way 
+    struct Node* new_node = getNode(8); 
+    sortedInsert(&head, new_node); 
+    new_node = getNode(5); 
+    sortedInsert(&head, new_node); 
+    new_node = getNode(3); 
+    sortedInsert(&head, new_node); 
+    new_node = getNode(10); 
+    sortedInsert(&head, new_node); 
+    new_node = getNode(12); 
+    sortedInsert(&head, new_node); 
+    new_node = getNode(9); 
+    sortedInsert(&head, new_node); 
+
+    cout << "Created Doubly Linked Listn"; 
+    printList(head); 
+    return 0; 
+}