자료구조_c언어_circularLinkedList_01

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
typedef struct ListNode {
    char data[4];
    struct ListNode *link;
}listNode;
 
typedef struct {
    listNode *head;
}linkedList_h;
 
linkedList_h* createLinkedList_h() {
    linkedList_h *CL;
    CL = (linkedList_h*)malloc(sizeof(linkedList_h));
    CL->head = NULL;
 
    return CL;
}
 
void printList(linkedList_h *CL) {
    listNode *p;
    printf("CL=(");
    p = CL->head;
    do {
        printf("%s", p->data);
        p = p->link;
        if (p != CL->head) {
            printf(",");
        }
    } while (p != CL->head);
    printf(")\n");
}
 
void insertFirstNode(linkedList_h *CL, char *x) {
    listNode *newNode, *temp;
    newNode = (listNode*)malloc(sizeof(listNode));
    strcpy(newNode->data, x);
    if (CL->head == NULL) {
        CL->head = newNode;
        newNode->link = newNode;
    }
    else {
        temp = CL->head;
        while (temp->link != CL->head) {
            temp = temp->link;
        }
        newNode->link = temp->link;
        temp->link = newNode;
        CL->head = newNode;
    }
}
 
void insertMiddleNode(linkedList_h *CL, listNode *pre, char *x) {
    listNode *newNode;
    newNode = (listNode*)malloc(sizeof(listNode));
    strcpy(newNode->data, x);
    if (pre == NULL) {
        CL->head = newNode;
        newNode->link = newNode;
    }
    else {
        newNode->link = pre->link;
        pre->link = newNode;
    }
}
 
void deleteNode(linkedList_h *CL, listNode *old) {
    listNode *pre;
    if (CL->head == NULL) {
        return;
    }
    if (CL->head->link == CL->head) {
        free(CL->head);
        CL->head = NULL;
        return;
    }
    else if (old == NULL) {
        return;
    }
    else {
        pre = CL->head;
        while (pre->link != old) {
            pre = pre->link;
        }
        pre->link = old->link;
        if (old == CL->head) {
            CL->head = old->link;
        }
        free(old);
    }
}