用c语言代码做班级通讯查询系统，基本要求，数据为本班全体同学信息，存储方式采用哈希表，可增、删、改信息，并可按电话号码和姓名查找，然后要可以文件读写

好的，下面是一个简单的班级通讯查询系统的C语言代码，基于哈希表实现：

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

#define MAX_SIZE 100 // 哈希表的最大容量

typedef struct Student {
    char name[20];
    char phone[20];
} Student;

typedef struct HashTable {
    Student *students[MAX_SIZE];
    int count;
} HashTable;

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

void insert(HashTable *ht, Student *s) {
    int index = hash(s->phone);
    while (ht->students[index] != NULL) {
        index = (index + 1) % MAX_SIZE;
    }
    ht->students[index] = s;
    ht->count++;
}

Student *search(HashTable *ht, char *key) {
    int index = hash(key);
    while (ht->students[index] != NULL) {
        if (strcmp(ht->students[index]->phone, key) == 0 || strcmp(ht->students[index]->name, key) == 0) {
            return ht->students[index];
        }
        index = (index + 1) % MAX_SIZE;
    }
    return NULL;
}

void delete(HashTable *ht, char *key) {
    int index = hash(key);
    while (ht->students[index] != NULL) {
        if (strcmp(ht->students[index]->phone, key) == 0 || strcmp(ht->students[index]->name, key) == 0) {
            ht->students[index] = NULL;
            ht->count--;
            return;
        }
        index = (index + 1) % MAX_SIZE;
    }
}

void update(HashTable *ht, char *key, char *new_name, char *new_phone) {
    Student *s = search(ht, key);
    if (s != NULL) {
        strcpy(s->name, new_name);
        strcpy(s->phone, new_phone);
    }
}

void save(HashTable *ht) {
    FILE *fp = fopen("students.txt", "w");
    if (fp == NULL) {
        printf("Error: cannot open file\n");
        return;
    }
    for (int i = 0; i < MAX_SIZE; i++) {
        if (ht->students[i] != NULL) {
            fprintf(fp, "%s %s\n", ht->students[i]->name, ht->students[i]->phone);
        }
    }
    fclose(fp);
}

void load(HashTable *ht) {
    FILE *fp = fopen("students.txt", "r");
    if (fp == NULL) {
        printf("Error: cannot open file\n");
        return;
    }
    char name[20], phone[20];
    while (fscanf(fp, "%s %s", name, phone) != EOF) {
        Student *s = (Student *)malloc(sizeof(Student));
        strcpy(s->name, name);
        strcpy(s->phone, phone);
        insert(ht, s);
    }
    fclose(fp);
}

void print_menu() {
    printf("1. Add student\n");
    printf("2. Search student\n");
    printf("3. Delete student\n");
    printf("4. Update student\n");
    printf("5. Save to file\n");
    printf("6. Load from file\n");
    printf("7. Exit\n");
}

int main() {
    HashTable ht = {0};
    int choice;
    char name[20], phone[20];
    while (1) {
        print_menu();
        printf("Enter your choice: ");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                printf("Enter student name: ");
                scanf("%s", name);
                printf("Enter student phone: ");
                scanf("%s", phone);
                Student *s = (Student *)malloc(sizeof(Student));
                strcpy(s->name, name);
                strcpy(s->phone, phone);
                insert(&ht, s);
                break;
            case 2:
                printf("Enter search key: ");
                scanf("%s", phone);
                Student *result = search(&ht, phone);
                if (result != NULL) {
                    printf("Name: %s\nPhone: %s\n", result->name, result->phone);
                } else {
                    printf("Not found\n");
                }
                break;
            case 3:
                printf("Enter delete key: ");
                scanf("%s", phone);
                delete(&ht, phone);
                break;
            case 4:
                printf("Enter search key: ");
                scanf("%s", phone);
                result = search(&ht, phone);
                if (result != NULL) {
                    printf("Enter new name: ");
                    scanf("%s", name);
                    printf("Enter new phone: ");
                    scanf("%s", phone);
                    update(&ht, result->phone, name, phone);
                } else {
                    printf("Not found\n");
                }
                break;
            case 5:
                save(&ht);
                break;
            case 6:
                load(&ht);
                break;
            case 7:
                exit(0);
            default:
                printf("Invalid choice\n");
                break;
        }
    }
    return 0;
}

这个代码实现了基本的增删改查功能，同时支持保存到文件和从文件读取。你可以根据自己的需要进行修改和扩展。