• Source 
    1. /* Given a reference (pointer to pointer) to the head
    2.    of a list and an int, appends a new node at the end  */
    3. void append(struct Node** head_ref, int new_data)
    4. {
    5.     /* 1. allocate node */
    6.     struct Node* new_node = (struct Node*) malloc(sizeof(struct Node));
    7.  
    8.     struct Node *last = *head_ref;  /* used in step 5*/
    9.  
    10.     /* 2. put in the data  */
    11.     new_node->data  = new_data;
    12.  
    13.     /* 3. This new node is going to be the last node, so make next 
    14.           of it as NULL*/
    15.     new_node->next = NULL;
    16.  
    17.     /* 4. If the Linked List is empty, then make the new node as head */
    18.     if (*head_ref == NULL)
    19.     {
    20.        *head_ref = new_node;
    21.        return;
    22.     }  
    23.  
    24.     /* 5. Else traverse till the last node */
    25.     while (last->next != NULL)
    26.         last = last->next;
    27.  
    28.     /* 6. Change the next of last node */
    29.     last->next = new_node;
    30.     return;    
    31. }