python字典怎样用c实现

Python中的字典是一种哈希表的实现，C语言中也可以使用哈希表来实现字典。

以下是一个简单的使用C语言实现字典的示例代码：

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

#define TABLE_SIZE 1000

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

typedef struct {
    Entry* entries[TABLE_SIZE];
} Dictionary;

int hash(char* key) {
    int hash = 0;
    for (int i = 0; i < strlen(key); i++) {
        hash = (hash * 31 + key[i]) % TABLE_SIZE;
    }
    return hash;
}

Entry* create_entry(char* key, char* value) {
    Entry* entry = malloc(sizeof(Entry));
    entry->key = malloc(strlen(key) + 1);
    entry->value = malloc(strlen(value) + 1);
    strcpy(entry->key, key);
    strcpy(entry->value, value);
    return entry;
}

Dictionary* create_dictionary() {
    Dictionary* dictionary = malloc(sizeof(Dictionary));
    memset(dictionary->entries, 0, sizeof(Entry*) * TABLE_SIZE);
    return dictionary;
}

void put(Dictionary* dictionary, char* key, char* value) {
    int index = hash(key);
    Entry* entry = dictionary->entries[index];
    while (entry != NULL) {
        if (strcmp(entry->key, key) == 0) {
            free(entry->value);
            entry->value = malloc(strlen(value) + 1);
            strcpy(entry->value, value);
            return;
        }
        entry = entry->next;
    }
    entry = create_entry(key, value);
    entry->next = dictionary->entries[index];
    dictionary->entries[index] = entry;
}

char* get(Dictionary* dictionary, char* key) {
    int index = hash(key);
    Entry* entry = dictionary->entries[index];
    while (entry != NULL) {
        if (strcmp(entry->key, key) == 0) {
            return entry->value;
        }
        entry = entry->next;
    }
    return NULL;
}

void delete(Dictionary* dictionary, char* key) {
    int index = hash(key);
    Entry* entry = dictionary->entries[index];
    Entry* prev = NULL;
    while (entry != NULL) {
        if (strcmp(entry->key, key) == 0) {
            if (prev == NULL) {
                dictionary->entries[index] = entry->next;
            } else {
                prev->next = entry->next;
            }
            free(entry->key);
            free(entry->value);
            free(entry);
            return;
        }
        prev = entry;
        entry = entry->next;
    }
}

void free_dictionary(Dictionary* dictionary) {
    for (int i = 0; i < TABLE_SIZE; i++) {
        Entry* entry = dictionary->entries[i];
        while (entry != NULL) {
            Entry* next = entry->next;
            free(entry->key);
            free(entry->value);
            free(entry);
            entry = next;
        }
    }
    free(dictionary);
}

int main() {
    Dictionary* dictionary = create_dictionary();
    put(dictionary, "one", "1");
    put(dictionary, "two", "2");
    put(dictionary, "three", "3");
    printf("%s\n", get(dictionary, "one"));
    printf("%s\n", get(dictionary, "two"));
    printf("%s\n", get(dictionary, "three"));
    delete(dictionary, "two");
    printf("%s\n", get(dictionary, "two"));
    free_dictionary(dictionary);
    return 0;
}

该代码使用了一个哈希表来实现字典，其中哈希函数使用了一种简单的方式来计算字符串的哈希值，每个桶中的元素使用链表来解决哈希冲突问题。使用该代码可以实现类似Python中字典的put、get和delete操作。