Add all possible insertion on linked lists (#82)

* all-possible-insertion-method-in-a-linked-list

* Rename All-possible-insertion-method.cpp to all-possible-insertion.cpp

* Update README.md

linked-lists/README.md

@@ -12,6 +12,7 @@
 2. [Doubly Linked List](c-or-cpp/doubly.cpp)
 
 3. [Circular Linked List](c-or-cpp/circular.cpp)
+4. [Insertion Linked List](c-or-cpp/all-possible-insertion.cpp)
 
 ### Java
 

linked-lists/c-or-cpp/all-possible-insertion.cpp

@@ -0,0 +1,135 @@
+/*A node can be added in three ways 
+1) At the front of the linked list 
+2) After a given node. 
+3) At the end of the linked list.*/
+
+//  all insertion methods on Linked List  
+
+#include <bits/stdc++.h> 
+using namespace std; 
+  
+// A linked list node  
+class Node  
+{  
+    public: 
+    int data;  
+    Node *next;  
+};  
+  
+/* Given a reference (pointer to pointer) 
+to the head of a list and an int, inserts 
+a new node on the front of the list. */
+void push(Node** head_ref, int new_data)  
+{  
+    /* 1. allocate node */
+    Node* new_node = new Node(); 
+  
+    /* 2. put in the data */
+    new_node->data = new_data;  
+  
+    /* 3. Make next of new node as head */
+    new_node->next = (*head_ref);  
+  
+    /* 4. move the head to point to the new node */
+    (*head_ref) = new_node;  
+}  
+  
+/* Given a node prev_node, insert a new node after the given  
+prev_node */
+void insertAfter(Node* prev_node, int new_data)  
+{  
+    /*1. check if the given prev_node is NULL */
+    if (prev_node == NULL)  
+    {  
+        cout<<"the given previous node cannot be NULL";  
+        return;  
+    }  
+  
+    /* 2. allocate new node */
+    Node* new_node = new Node(); 
+  
+    /* 3. put in the data */
+    new_node->data = new_data;  
+  
+    /* 4. Make next of new node as next of prev_node */
+    new_node->next = prev_node->next;  
+  
+    /* 5. move the next of prev_node as new_node */
+    prev_node->next = new_node;  
+}  
+  
+/* Given a reference (pointer to pointer) to the head  
+of a list and an int, appends a new node at the end */
+void append(Node** head_ref, int new_data)  
+{  
+    /* 1. allocate node */
+    Node* new_node = new Node(); 
+  
+    Node *last = *head_ref; /* used in step 5*/
+  
+    /* 2. put in the data */
+    new_node->data = new_data;  
+  
+    /* 3. This new node is going to be  
+    the last node, so make next of  
+    it as NULL*/
+    new_node->next = NULL;  
+  
+    /* 4. If the Linked List is empty, 
+    then make the new node as head */
+    if (*head_ref == NULL)  
+    {  
+        *head_ref = new_node;  
+        return;  
+    }  
+  
+    /* 5. Else traverse till the last node */
+    while (last->next != NULL)  
+        last = last->next;  
+  
+    /* 6. Change the next of last node */
+    last->next = new_node;  
+    return;  
+}  
+  
+// This function prints contents of 
+// linked list starting from head  
+void printList(Node *node)  
+{  
+    while (node != NULL)  
+    {  
+        cout<<" "<<node->data;  
+        node = node->next;  
+    }  
+}  
+  
+/* Driver code*/
+int main()  
+{  
+    /* Start with the empty list */
+    Node* head = NULL;  
+      
+    // Insert 6. So linked list becomes 6->NULL  
+    append(&head, 6);  
+      
+    // Insert 7 at the beginning.  
+    // So linked list becomes 7->6->NULL  
+    push(&head, 7);  
+      
+    // Insert 1 at the beginning.  
+    // So linked list becomes 1->7->6->NULL  
+    push(&head, 1);  
+      
+    // Insert 4 at the end. So  
+    // linked list becomes 1->7->6->4->NULL  
+    append(&head, 4);  
+      
+    // Insert 8, after 7. So linked  
+    // list becomes 1->7->8->6->4->NULL  
+    insertAfter(head->next, 8);  
+      
+    cout<<"Created Linked list is: ";  
+    printList(head);  
+      
+    return 0;  
+}