Delete a node from link list

int listDel(int delData) {

    NodeType *ptr;

    ptr = listHead;

    while (ptr) {

         if(ptr->data == delData) {

            printf("data = %d key found\n", ptr->data);

            if(ptr == listHead) {

               printf("This is a head\n");

               if(ptr->next) { 

                  listHead = ptr->next; 

                  (ptr->next)->prev = 0;

               }

               else {

                  listHead = 0;

               }

            }

            else if(ptr == listTail) {

               printf("This is a tail\n");

               listTail = ptr->prev;

               (ptr->prev)->next = 0;

            }

            else {

               printf("This is a middle\n");

               // connect previous to next

               (ptr->prev)->next = ptr->next;

               // connect next to previous

               ptr->next = (ptr->prev)->next;

            }

            // disconnect

            ptr->prev = 0;

            ptr->next = 0;

            free(ptr); // delete

            break;

         }

         ptr = ptr->next;

    }

    return 0;

}

int main() {

    listAdd(1);

    listAdd(2);

    listAdd(3);

    listAdd(4);

    listAdd(5);

    listAdd(6);

    listShow();

    printf("\n");

    listDel(1);

    listDel(6);

    listDel(4);

    listDel(7);

    listDel(2);

    printf("\n");

    listShow();

   

    return 0;

}

1st node added (1)

data = 1

data = 2

data = 3

data = 4

data = 5

data = 6

data = 1 key found

This is a head

data = 6 key found

This is a tail

data = 4 key found

This is a middle

data = 2 key found

This is a head

data = 3

data = 5