哈希表实现

hash_table.h 

//
// Created on 2021/4/14.
//

#ifndef C_HASH_TABLE_H
#define C_HASH_TABLE_H

#ifdef __cplusplus
extern "C" {
#endif

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


    static long long n;

    struct hash_table {
        char *key;
        char *value;

        struct hash_table *next;
    } __attribute__((__packed__));

    struct hash_table *first_point;
    struct hash_table *current_point;

    /**
     * 哈希表根据key，获取值,时间复杂度：O(N)
     * @param key 键
     * @return 值得类型不确定，理论上可以为任何类型
     */
    void *hash_table_get(char *key) {
        struct hash_table *temp = first_point;
        while (temp != NULL) {
            if (temp->key == key) {
                return temp->value;
            } else {
                temp = temp->next;
            }
        }
        return NULL;
    }

    /**
     * 将键值对存入哈希表，时间复杂度：O(1)
     * @param key 键
     * @param value 值
     * @return
     */
    int hash_table_put(char *key, char *value) {
        struct hash_table *temp_hash_table;
        temp_hash_table = (struct hash_table*) malloc(sizeof(struct hash_table));
        temp_hash_table->key = key;
        temp_hash_table->value = value;
        temp_hash_table->next = NULL;

        if (current_point == NULL) {
            first_point = temp_hash_table;
            current_point = temp_hash_table;
        } else {
            current_point->next = temp_hash_table;
            current_point->next->next = NULL;
            current_point = current_point->next;
            current_point->next = NULL;
        }
        return 0;
    }

    /**
     * 移除某个键值对
     * @param key 键
     * @return
     */
    //int remove(char *key);

    /**
     * 哈希表大小，即键的个数,时间复杂度：O(N)
     * @return
     */
    long long hash_table_size() {
        struct hash_table *temp = first_point;
        while (temp != NULL) {
            n += 1;
            temp = temp->next;
        }
        return n;
    }

    /**
     * 判断哈希表是否为空，时间复杂度：O(1)
     * @return
     */
    bool hash_table_isEmpty() {
        return first_point == NULL;
    }

    /**
     * 哈希表所有键值对打印
     * @return
     */
    char *toString();

#ifdef __cplusplus
}
#endif

#endif //C_HASH_TABLE_H

main.c

#include <stdio.h>
#include "include/data_struct/hash_table.h"

int main() {
    printf("Hello, World!\n");
    hash_table_put("1", "2");
    hash_table_put("3", "4");
    hash_table_put("5", "6");
    hash_table_put("8", "9");
    hash_table_put("10", "11");
    hash_table_put("12", "13");
    hash_table_put("17", "18");

    char *value = "";
    value = hash_table_get("13");
    if (value == NULL) {
        printf("The hash table value of key is NULL\n");
    } else {
        printf("The hash table value of key 13 is %s\n", value);
    }

    printf("The hash table size is %ld\n", hash_table_size());

    if (hash_table_isEmpty()) {
        printf("The hash table is empty\n");
        printf("The hash table is %d\n", hash_table_isEmpty());
    } else {
        printf("The hash table is not empty\n");
        printf("The hash table is %d\n", hash_table_isEmpty());
    }
    return 0;
}

待续！