数据结构之c语言链表

# include <stdio.h># include <malloc.h># include <stdlib.h>typedef struct Node{int data; //数据域struct Node * pNext; //指针域}NODE, *PNODE; //NODE等价于struct Node    PNODE等价于struct Node *//函数声明PNODE create_list(void);  //创建链表void traverse_list(PNODE pHead);  //遍历链表bool is_empty(PNODE pHead);  //判断链表是否为空int length_list(PNODE);  //求链表长度bool insert_list(PNODE pHead, int pos, int val);  //在pHead所指向链表的第pos个节点的前面插入一个新的结点，该节点的值是val， 并且pos的值是从1开始bool delete_list(PNODE pHead, int pos, int * pVal);  //删除链表第pos个节点，并将删除的结点的值存入pVal所指向的变量中,  并且pos的值是从1开始void sort_list(PNODE);  //对链表进行排序int main(void){PNODE pHead = NULL; //等价于 struct Node * pHead = NULL;int val;pHead = create_list();  //create_list()功能：创建一个非循环单链表，并将该链表的头结点的地址付给pHeadtraverse_list(pHead);//insert_list(pHead, -4, 33);if ( delete_list(pHead, 4, &val) ){printf("删除成功，您删除的元素是: %d\n", val);}else{printf("删除失败!您删除的元素不存在!\n");}traverse_list(pHead);//int len = length_list(pHead);//printf("链表的长度是%d\n", len);//sort_list(pHead);//traverse_list(pHead);/*if ( is_empty(pHead) )printf("链表为空!\n");elseprintf("链表不空!\n");*/return 0;}PNODE create_list(void){int len;  //用来存放有效节点的个数int i;int val; //用来临时存放用户输入的结点的值//分配了一个不存放有效数据的头结点PNODE pHead = (PNODE)malloc(sizeof(NODE));if (NULL == pHead){printf("分配失败, 程序终止!\n");exit(-1);}PNODE pTail = pHead;pTail->pNext = NULL;printf("请输入您需要生成的链表节点的个数: len = ");scanf("%d", &len);for (i=0; i<len; ++i){printf("请输入第%d个节点的值: ", i+1);scanf("%d", &val);PNODE pNew = (PNODE)malloc(sizeof(NODE));if (NULL == pNew){printf("分配失败, 程序终止!\n");exit(-1);}pNew->data = val;pTail->pNext = pNew;pNew->pNext = NULL;pTail = pNew;}return pHead;}void traverse_list(PNODE pHead){PNODE p = pHead->pNext;while (NULL != p){printf("%d  ", p->data);p = p->pNext;}printf("\n");return;}bool is_empty(PNODE pHead){if (NULL == pHead->pNext)return true;elsereturn false;}int length_list(PNODE pHead){PNODE p = pHead->pNext;int len = 0;while (NULL != p){++len;p = p->pNext;}return len;}void sort_list(PNODE pHead){int i, j, t;int len = length_list(pHead);PNODE p, q;for (i=0,p=pHead->pNext; i<len-1; ++i,p=p->pNext){for (j=i+1,q=p->pNext; j<len; ++j,q=q->pNext){if (p->data > q->data)  //类似于数组中的:  a[i] > a[j]{t = p->data;//类似于数组中的:  t = a[i];p->data = q->data; //类似于数组中的:  a[i] = a[j];q->data = t; //类似于数组中的:  a[j] = t;}}}return;}//在pHead所指向链表的第pos个节点的前面插入一个新的结点，该节点的值是val， 并且pos的值是从1开始bool insert_list(PNODE pHead, int pos, int val){int i = 0;PNODE p = pHead;while (NULL!=p && i<pos-1){p = p->pNext;++i;}if (i>pos-1 || NULL==p)return false;//如果程序能执行到这一行说明p已经指向了第pos-1个结点,但第pos-1个节点是否存在无所谓//分配新的结点PNODE pNew = (PNODE)malloc(sizeof(NODE));if (NULL == pNew){printf("动态分配内存失败!\n");exit(-1);}pNew->data = val;//将新的结点存入p节点的后面PNODE q = p->pNext;p->pNext = pNew;pNew->pNext = q;return true;}bool delete_list(PNODE pHead, int pos, int * pVal){int i = 0;PNODE p = pHead;while (NULL!=p->pNext && i<pos-1){p = p->pNext;++i;}if (i>pos-1 || NULL==p->pNext)return false;//如果程序能执行到这一行说明p已经指向了第pos-1个结点，并且第pos个节点是存在的PNODE q = p->pNext;  //q指向待删除的结点*pVal = q->data;  //删除p节点后面的结点p->pNext = p->pNext->pNext;//释放q所指向的节点所占的内存free(q);q = NULL;return true;}