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node/twoFontNode.c

+//
+// Created by bh on 22-12-13.
+//
+#include <stdio.h>
+#include <malloc.h>
+#include <string.h>
+#include <stdlib.h>
+
+struct node {
+    char name[10];
+    int age;
+    struct node *prev;
+    struct node *next;
+};
+
+// create an empty node
+struct node *create() {
+    struct node *node = (struct node *) malloc(sizeof(struct node));
+    if (node == NULL) {
+        perror("malloc node failed!");
+        exit(1);
+    }
+    return node;
+}
+
+
+// insert new node
+void insertNode(struct node *prevNode, struct node *newNode) {
+    if (prevNode->prev != NULL && prevNode->next != NULL) {
+        if ((prevNode->next == prevNode->prev) && (prevNode->next == prevNode)) { // if only head
+            struct node *head = prevNode;
+
+            prevNode->prev = newNode;
+            prevNode->next = newNode;
+
+            newNode->prev = head;
+            newNode->next = head;
+        } else { // not only head node
+            struct node *nextNode = prevNode->next;
+
+            prevNode->next = newNode;
+
+            newNode->prev = prevNode;
+            newNode->next = nextNode;
+
+            nextNode->prev = newNode;
+
+        }
+
+    }
+}
+
+// delete a node
+void delNode(struct node *delNode) {
+    struct node *preNode = delNode->prev;
+    struct node *nextNode = delNode->next;
+
+    preNode->next = nextNode;
+    nextNode->prev = preNode;
+
+    free(delNode);
+    delNode = NULL;
+}
+// print node list
+void printChain(struct node *head) {
+    struct node *nextNode;
+    nextNode = head;
+    printf("name=%s,age=%d,===prev=%p,this=%p,next=%p \n", nextNode->name, nextNode->age, nextNode->prev, nextNode,
+           nextNode->next);
+    while (nextNode->next != head) {
+        nextNode = nextNode->next;
+        printf("name=%s,age=%d,===prev=%p,this=%p,next=%p \n", nextNode->name, nextNode->age, nextNode->prev, nextNode,
+               nextNode->next);
+    }
+
+}
+
+int main() {
+
+    struct node *head = create();
+    head->age = 10;
+    strcpy(head->name, "node0");
+    head->next = head;
+    head->prev = head;
+
+    struct node *node1 = create();
+    node1->age = 18;
+    strcpy(node1->name, "node1");
+    insertNode(head, node1);
+
+    struct node *node2 = create();
+    node2->age = 19;
+    strcpy(node2->name, "node2");
+    insertNode(node1, node2);
+
+    struct node *node3 = create();
+    node3->age = 20;
+    strcpy(node3->name, "node3");
+    insertNode(node2, node3);
+
+    struct node *node4 = create();
+    node4->age = 21;
+    strcpy(node4->name, "node4");
+    insertNode(node1, node4);
+
+    struct node *node5 = create();
+    node5->age = 21;
+    strcpy(node5->name, "node5");
+    insertNode(node2, node5);
+
+    printChain(head);
+
+    printf("===================================\n");
+
+    delNode(node2);
+
+    printChain(head);
+    return 0;
+}
+
+
+