用 C 语言写一个哈希表

这是一个使用 C 语言实现哈希表的简单示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define TABLE_SIZE 10

typedef struct {
  char *key;
  char *value;
} HashEntry;

typedef struct {
  HashEntry *entry;
} HashTable;

HashTable *create_hash_table() {
  HashTable *table = (HashTable *)malloc(sizeof(HashTable));
  table->entry = (HashEntry *)malloc(sizeof(HashEntry) * TABLE_SIZE);
  for (int i = 0; i < TABLE_SIZE; i++) {
    table->entry[i].key = NULL;
    table->entry[i].value = NULL;
  }
  return table;
}

int hash(char *key) {
  int sum = 0;
  for (int i = 0; i < strlen(key); i++) {
    sum += key[i];
  }
  return sum % TABLE_SIZE;
}

void put(HashTable *table, char *key, char *value) {
  int index = hash(key);
  while (table->entry[index].key != NULL) {
    if (strcmp(table->entry[index].key, key) == 0) {
      break;
    }
    index = (index + 1) % TABLE_SIZE;
  }
  table->entry[index].key = key;
  table->entry[index].value = value;
}

char *get(HashTable *table, char *key) {
  int index = hash(key);
  while (table->entry[index].key != NULL) {
    if (strcmp(table->entry[index].key, key) == 0) {
      return table->entry[index].value;
    }
    index = (index + 1) % TABLE_SIZE;
  }
  return NULL;
}

int main() {
  HashTable *table = create_hash_table();
  put(table, "foo", "bar");
  put(table, "hello", "world");
  printf("%s\n", get(table, "foo"));
  printf("%s\n", get(table, "hello"));
  return 0;
}

这个示例实现了哈希表的基本功能，包括创建哈希表、插入元素、查找元素。这里使用了链地址法来解决冲突。