酒店管理系统代码：登记入住，查询客户信息，查询客房信息，办理退房，退出系统

以下是一个简单的酒店管理系统的代码示例，包括登记入住、查询客户信息、查询客房信息、办理退房和退出系统功能：

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

#define MAX_ROOM_NUM 100
#define MAX_NAME_LEN 20
#define MAX_PHONE_LEN 15

typedef struct {
    int room_num;
    int occupied;
    char guest_name[MAX_NAME_LEN];
    char guest_phone[MAX_PHONE_LEN];
} Room;

Room rooms[MAX_ROOM_NUM];

void init_rooms() {
    int i;
    for (i = 0; i < MAX_ROOM_NUM; i++) {
        rooms[i].room_num = i + 1;
        rooms[i].occupied = 0;
        strcpy(rooms[i].guest_name, "");
        strcpy(rooms[i].guest_phone, "");
    }
}

void check_in() {
    int room_num;
    char guest_name[MAX_NAME_LEN];
    char guest_phone[MAX_PHONE_LEN];
    printf("请输入房间号: ");
    scanf("%d", &room_num);
    if (room_num < 1 || room_num > MAX_ROOM_NUM) {
        printf("无效的房间号\n");
        return;
    }
    if (rooms[room_num - 1].occupied) {
        printf("房间已被占用\n");
        return;
    }
    printf("请输入客人姓名: ");
    scanf("%s", guest_name);
    printf("请输入客人电话: ");
    scanf("%s", guest_phone);
    rooms[room_num - 1].occupied = 1;
    strcpy(rooms[room_num - 1].guest_name, guest_name);
    strcpy(rooms[room_num - 1].guest_phone, guest_phone);
    printf("登记成功\n");
}

void check_out() {
    int room_num;
    printf("请输入房间号: ");
    scanf("%d", &room_num);
    if (room_num < 1 || room_num > MAX_ROOM_NUM) {
        printf("无效的房间号\n");
        return;
    }
    if (!rooms[room_num - 1].occupied) {
        printf("房间未被占用\n");
        return;
    }
    printf("客人姓名: %s\n", rooms[room_num - 1].guest_name);
    printf("客人电话: %s\n", rooms[room_num - 1].guest_phone);
    rooms[room_num - 1].occupied = 0;
    strcpy(rooms[room_num - 1].guest_name, "");
    strcpy(rooms[room_num - 1].guest_phone, "");
    printf("退房成功\n");
}

void search_guest() {
    char guest_name[MAX_NAME_LEN];
    int i, found = 0;
    printf("请输入客人姓名: ");
    scanf("%s", guest_name);
    for (i = 0; i < MAX_ROOM_NUM; i++) {
        if (strcmp(rooms[i].guest_name, guest_name) == 0) {
            printf("房间号: %d\n", rooms[i].room_num);
            printf("客人电话: %s\n", rooms[i].guest_phone);
            found = 1;
        }
    }
    if (!found) {
        printf("未找到该客人\n");
    }
}

void search_room() {
    int room_num, i;
    printf("请输入房间号: ");
    scanf("%d", &room_num);
    if (room_num < 1 || room_num > MAX_ROOM_NUM) {
        printf("无效的房间号\n");
        return;
    }
    if (!rooms[room_num - 1].occupied) {
        printf("房间未被占用\n");
        return;
    }
    printf("客人姓名: %s\n", rooms[room_num - 1].guest_name);
    printf("客人电话: %s\n", rooms[room_num - 1].guest_phone);
}

void print_menu() {
    printf("1. 登记入住\n");
    printf("2. 办理退房\n");
    printf("3. 查询客户信息\n");
    printf("4. 查询客房信息\n");
    printf("5. 退出系统\n");
}

int main() {
    int choice;
    init_rooms();
    while (1) {
        print_menu();
        printf("请选择操作: ");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                check_in();
                break;
            case 2:
                check_out();
                break;
            case 3:
                search_guest();
                break;
            case 4:
                search_room();
                break;
            case 5:
                return 0;
            default:
                printf("无效的操作\n");
                break;
        }
    }
    return 0;
}

在该代码中，我们定义了一个Room结构体来表示酒店房间的信息，包括房间号、是否占用和客人姓名、电话等信息。使用init_rooms函数来初始化酒店房间信息。check_in函数用于登记客人入住，check_out函数用于办理退房，search_guest函数用于查询客户信息，search_room函数用于查询客房信息。最后，使用一个循环来不断显示菜单，接收用户输入并调用相应的函数。