linked list in c 2b 2b using class insert delete display in array

1#include <iostream>
2using namespace std;
3 
4// A linked list node
5struct Node
6{
7   int data;
8   struct Node *next;
9};
10//insert a new node in front of the list
11void push(struct Node** head, int node_data)
12{
13   /* 1. create and allocate node */
14   struct Node* newNode = new Node;
15 
16   /* 2. assign data to node */
17   newNode->data = node_data;
18 
19   /* 3. set next of new node as head */
20   newNode->next = (*head);
21 
22   /* 4. move the head to point to the new node */
23   (*head) = newNode;
24}
25 
26//insert new node after a given node
27void insertAfter(struct Node* prev_node, int node_data)
28{
29  /*1. check if the given prev_node is NULL */
30if (prev_node == NULL)
31{
32   cout<<"the given previous node is required,cannot be NULL"; return; } 
33 
34   /* 2. create and allocate new node */
35   struct Node* newNode =new Node; 
36 
37   /* 3. assign data to the node */
38   newNode->data = node_data;
39 
40   /* 4. Make next of new node as next of prev_node */
41   newNode->next = prev_node->next;
42 
43    /* 5. move the next of prev_node as new_node */
44    prev_node->next = newNode;
45}
46 
47/* insert new node at the end of the linked list */
48void append(struct Node** head, int node_data)
49{
50/* 1. create and allocate node */
51struct Node* newNode = new Node;
52 
53struct Node *last = *head; /* used in step 5*/
54 
55/* 2. assign data to the node */
56newNode->data = node_data;
57 
58/* 3. set next pointer of new node to null as its the last node*/
59newNode->next = NULL;
60 
61/* 4. if list is empty, new node becomes first node */
62if (*head == NULL)
63{
64*head = newNode;
65return;
66}
67 
68/* 5. Else traverse till the last node */
69while (last->next != NULL)
70last = last->next;
71 
72/* 6. Change the next of last node */
73last->next = newNode;
74return;
75}
76 
77// display linked list contents
78void displayList(struct Node *node)
79{
80   //traverse the list to display each node
81   while (node != NULL)
82   {
83      cout<<node->data<<"-->";
84      node = node->next;
85   }
86 
87if(node== NULL)
88cout<<"null"; 
89} 
90/* main program for linked list*/
91int main() 
92{ 
93/* empty list */
94struct Node* head = NULL; 
95 
96// Insert 10.
97append(&head, 10); 
98 
99// Insert 20 at the beginning. 
100push(&head, 20); 
101 
102// Insert 30 at the beginning. 
103push(&head, 30); 
104 
105// Insert 40 at the end. 
106append(&head, 40); // 
107 
108Insert 50, after 20. 
109insertAfter(head->next, 50);
110 
111cout<<"Final linked list: "<<endl;
112displayList(head);
113 
114return 0;
115}
116