Linked List in C (1)

1 #include<stdio.h>
  2 #include<stdlib.h>
  3 
  4 typedef struct _Node
  5 {
  6     int data;
  7     struct _Node *next;
  8 }Node;
  9 
 10 Node *newList();
 11 Node *insertNode(Node *head, int data);
 12 void printList(Node *head);
 13 Node* insert_at_tail(Node *tail, int data);
 14 void deleteList(Node *head);
 15 int getMax(Node *head);
 16 
 17 int getMax(Node *head)
 18 {
 19     Node *temp = head;
 20     int maxVal = head->data;
 21     while(temp != NULL)
 22     {
 23         if(maxVal < temp->data)
 24         {
 25             maxVal = temp->data;
 26         }
 27         temp = temp->next;            
 28     }
 29     return retVal;
 30 }
 31 
 32 Node *insertNode(Node *head, int data)
 33 {
 34     Node *newNode = malloc(sizeof(Node));
 35     if(newNode == NULL)
 36     {
 37         printf("newNode is NULL!\n");
 38         exit(-1);
 39     }
 40     Node *temp = head;
 41     while( temp->next != NULL)
 42     {
 43         temp = temp->next;
 44     }
 45     newNode->data = data;
 46     newNode->next = temp->next;
 47     temp->next = newNode;
 48 
 49     return newNode;
 50 }
 51 
 52 /* Make a new list. Create a dummy head node to represent an empty list, and it returns a head of a new empty list*/
 53 Node *newList()
 54 {
 55     Node *dummyNode = malloc(sizeof(Node));
 56     if(dummyNode == NULL)
 57     {
 58         printf("dummyNode is NULL! \n");
 59         exit(-1);
 60     }
 61     return dummyNode;    
 62 }
 63 
 64 /* Insert at tail */
 65 Node *insert_at_tail(Node *tail, int data)
 66 {
 67     Node *newNode = malloc(sizeof(Node));
 68     if(newNode == NULL)
 69     {
 70         printf("newNode is NULL!\n");
 71         exit(-1);
 72     }
 73     newNode->data = data;
 74     newNode->next = NULL;
 75     tail->next = newNode;
 76     return newNode;            
 77 }
 78 
 79 /* Delete an entire list */
 80 void deleteList(Node *head)
 81 {    
 82     ListNode *temp = head;
 83     ListNode *delNode;
 84 
 85     while(temp != NULL)
 86     {    
 87         delNode = temp;
 88         temp = temp->next;
 89         delNode->next = NULL;
 90         free(delNode);
 91     }
 92     free(temp);
 93 }
 94 
 95 void printList(Node *head)
 96 {
 97     Node *temp = head;
 98     while(temp != NULL)
 99     {
100         printf("%d  \n",temp->data);
101         temp = temp->next;        
102     }    
103 }