C语言实现的哈希表
哈希表可以简单理解为多个链表的集合，将每个新的成员根据其哈希值进行分类，这样可以加快链表的查找速度
参考：https://www.cnblogs.com/s-b-b/p/6208565.html

#include <stdio.h>#include <stdlib.h>#include <string.h>#define HASHSIZE 10typedef unsigned int uint;/*定义一个链表的节点*/typedef struct Node{ char key[17]; char value[4]; struct Node *next;}Node;/*定义一组链表*/Node *node[HASHSIZE];/*初始化:为链表头开辟空间*/int init(Node *node){ node = (Node *)malloc(sizeof(Node)); if(NULL == node) return 1; bzero(node, sizeof(Node)); return 0;}/*计算哈希值*/uint hash(const char *key){ uint hash = 0; for(; *key; ++key) { hash = hash*33+*key; } return hash%HASHSIZE;}/*查找:根据哈希值得出index, 然后到对应的链表中查找*/Node *lookup(const char *key){ Node *np; uint index; index = hash(key); for(np = node[index];np;np = np->next){ if(!strcmp(key, np->key)) return np; } return NULL;}/*插入：先查找该值是否存在，然后计算哈希值，插入对应的链表*/uint install(const char *key, const char *value){ uint index; Node *np; if(!(np = lookup(key))){ index = hash(key); np = (Node*)malloc(sizeof(Node)); if(!np) return 1; strcpy(np->key, key); strcpy(np->value, value); np->next = node[index]; node[index] = np; } return 0;}/*例：*/int main(void){ /*为哈希表插入一组数据*/ char key[17] = "10.10.16.31"; char value[4] = "001"; install(key, value); char key1[17] = "10.10.16.32"; char value1[4] = "002"; install(key1, value1); char key2[17] = "10.10.16.33"; char value2[4] = "003"; install(key2, value2); char key3[17] = "10.10.16.34"; char value3[4] = "004"; install(key3, value3); char key4[17] = "10.10.16.41"; char value4[4] = "005"; install(key4, value4); Node *np; /*哈希表初始化：如果不为表头赋值的话可以省略*/ int i,j; for(i=0;i<HASHSIZE;i++){ init(node[i]); } /*遍历哈希表*/ for(i=0; i<HASHSIZE; i++) { if(node[i]){ printf("i:%d, key:%s, value:%s\n", i, node[i]->key, node[i]->value); np = node[i]->next; while(np){ printf("key:%s, value:%s\n", np->key, np->value); np = np->next; } } } return 0;}