insert last in linked list c++

// A complete working C program to demonstrate all insertion methods 
// on Linked List 
#include <stdio.h> 
#include <stdlib.h> 
  
// A linked list node 
struct Node 
{ 
  int data; 
  struct 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(struct Node** head_ref, int new_data) 
{ 
    /* 1. allocate node */
    struct Node* new_node = (struct Node*) malloc(sizeof(struct 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(struct Node* prev_node, int new_data) 
{ 
    /*1. check if the given prev_node is NULL */
    if (prev_node == NULL) 
    { 
      printf("the given previous node cannot be NULL"); 
      return; 
    } 
  
    /* 2. allocate new node */
    struct Node* new_node =(struct Node*) malloc(sizeof(struct 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(struct Node** head_ref, int new_data) 
{ 
    /* 1. allocate node */
    struct Node* new_node = (struct Node*) malloc(sizeof(struct Node)); 
  
    struct 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(struct Node *node) 
{ 
  while (node != NULL) 
  { 
     printf(" %d ", node->data); 
     node = node->next; 
  } 
} 
  
/* Driver program to test above functions*/
int main() 
{ 
  /* Start with the empty list */
  struct 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); 
  
  printf("\n Created Linked list is: "); 
  printList(head); 
  
  return 0; 
}