用c语言写一个链表实现一个电话号码本的功能，至少要包括，录入，删除，按使用频率排序，列出（显示全部），根据姓名查找号码，根据号码查找姓名等功能。

在 C 语言中，我们可以创建一个简单的链表结构来实现电话号码本的功能。这里是一个基础的示例，包含了一个`Node`结构用于存储电话记录，以及相应的函数来实现你的需求：

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

// 定义 Node 结构
typedef struct PhoneBookNode {
    char name[50];
    char number[20];
    int frequency; // 使用频率
    struct PhoneBookNode* next;
} PhoneBookNode;

// 创建新的节点
PhoneBookNode* createNode(char* name, char* number) {
    PhoneBookNode* newNode = (PhoneBookNode*)malloc(sizeof(PhoneBookNode));
    if (newNode != NULL) {
        strcpy(newNode->name, name);
        strcpy(newNode->number, number);
        newNode->frequency = 0;
        newNode->next = NULL;
    }
    return newNode;
}

// 录入电话号码
void insert(PhoneBookNode** head, char* name, char* number) {
    PhoneBookNode* newNode = createNode(name, number);
    if (*head == NULL) {
        *head = newNode;
    } else {
        PhoneBookNode* temp = *head;
        while (temp->next != NULL) {
            temp = temp->next;
        }
        temp->next = newNode;
    }
}

// 删除电话号码
void deleteEntry(PhoneBookNode** head, char* name) {
    if (*head == NULL) return;
    
    if ((*head)->name[0] == '\0') {
        free(*head);
        *head = (*head)->next;
        return;
    }

    PhoneBookNode* temp = *head;
    PhoneBookNode* prev = NULL;
    
    while (temp != NULL && strcmp(temp->name, name) != 0) {
        prev = temp;
        temp = temp->next;
    }

    if (temp == NULL) return; // 没找到

    if (prev == NULL) {
        *head = temp->next;
    } else {
        prev->next = temp->next;
    }

    free(temp);
}

// 计算并更新使用频率
void updateFrequency(PhoneBookNode* node) {
    for (node = node->next; node != NULL; node = node->next) {
        node->frequency++;
    }
}

// 根据使用频率排序链表
void sortByFrequency(PhoneBookNode** head) {
    if (*head == NULL || (*head)->next == NULL) return;

    PhoneBookNode* sortedList = *head;
    PhoneBookNode* unsortedList = *head->next;
    int count = 0;

    while (unsortedList != NULL) {
        PhoneBookNode* temp = unsortedList;
        PhoneBookNode* prev = NULL;
        
        while (count < temp->frequency) {
            if (prev == NULL) {
                sortedList = temp;
            } else {
                prev->next = temp;
            }
            temp = temp->next;
            count++;
        }

        if (temp != NULL) {
            prev->next = temp;
            temp = unsortedList;
            unsortedList = temp->next;
        } else {
            prev->next = NULL;
        }
    }

    *head = sortedList;
}

// 显示全部联系人
void displayPhoneBook(PhoneBookNode* node) {
    while (node != NULL) {
        printf("Name: %s, Number: %s, Frequency: %d\n", node->name, node->number, node->frequency);
        node = node->next;
    }
}

// 查找联系人根据名字
char* findByName(PhoneBookNode* node, char* name) {
    while (node != NULL) {
        if (strcmp(node->name, name) == 0) {
            return node->number;
        }
        node = node->next;
    }
    return "Not found";
}

// 查找联系人根据号码
char* findNumberByName(PhoneBookNode* node, char* number) {
    while (node != NULL) {
        if (strcmp(node->number, number) == 0) {
            return node->name;
        }
        node = node->next;
    }
    return "Not found";
}

int main() {
    // 初始化头节点
    PhoneBookNode* phoneBookHead = NULL;

    // 插入、删除、操作等...

    return 0;
}