用c语言编写一个后端代码，实现校园图书馆选座网页的人机交互

好的，下面是一个简单的示例代码，可以实现校园图书馆选座网页的人机交互：

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

// 定义座位结构体
struct Seat {
    int seat_id; // 座位编号
    int is_available; // 该座位是否可用
    int is_reserved; // 该座位是否被预约
    int is_occupied; // 该座位是否被占用
};

// 初始化座位信息
void init_seats(struct Seat seats[], int num_seats) {
    for (int i = 0; i < num_seats; i++) {
        seats[i].seat_id = i + 1;
        seats[i].is_available = 1;
        seats[i].is_reserved = 0;
        seats[i].is_occupied = 0;
    }
}

// 处理选座请求
void handle_reserve_seat_request(int seat_id, struct Seat seats[], int num_seats) {
    // 判断座位是否可用
    if (seat_id < 1 || seat_id > num_seats) {
        printf("Invalid seat number!\n");
        return;
    }
    if (seats[seat_id - 1].is_available) {
        // 判断座位是否被预约
        if (seats[seat_id - 1].is_reserved) {
            // 座位已被预约，返回预约失败信息
            printf("The seat has been reserved!\n");
        } else {
            // 预约座位
            seats[seat_id - 1].is_reserved = 1;
            seats[seat_id - 1].is_available = 0;
            printf("Reserve seat %d successfully!\n", seat_id);
        }
    } else {
        // 座位不可用，返回预约失败信息
        printf("The seat is not available!\n");
    }
}

// 处理取消预约请求
void handle_cancel_reserve_request(int seat_id, struct Seat seats[], int num_seats) {
    // 判断座位是否已被预约
    if (seat_id < 1 || seat_id > num_seats) {
        printf("Invalid seat number!\n");
        return;
    }
    if (seats[seat_id - 1].is_reserved) {
        // 取消预约
        seats[seat_id - 1].is_reserved = 0;
        seats[seat_id - 1].is_available = 1;
        printf("Cancel reservation of seat %d successfully!\n", seat_id);
    } else {
        // 座位未被预约，返回取消预约失败信息
        printf("The seat has not been reserved!\n");
    }
}

// 处理落座请求
void handle_occupy_seat_request(int seat_id, struct Seat seats[], int num_seats) {
    // 判断座位是否已被预约
    if (seat_id < 1 || seat_id > num_seats) {
        printf("Invalid seat number!\n");
        return;
    }
    if (seats[seat_id - 1].is_reserved) {
        // 判断座位是否已被占用
        if (seats[seat_id - 1].is_occupied) {
            // 座位已被占用，返回落座失败信息
            printf("The seat has been occupied!\n");
        } else {
            // 座位未被占用，占用座位
            seats[seat_id - 1].is_occupied = 1;
            seats[seat_id - 1].is_reserved = 0;
            printf("Occupy seat %d successfully!\n", seat_id);
        }
    } else {
        // 座位未被预约，释放座位
        seats[seat_id - 1].is_available = 1;
        printf("Release seat %d successfully!\n", seat_id);
    }
}

int main() {
    // 初始化座位信息
    int num_seats = 100;
    struct Seat seats[num_seats];
    init_seats(seats, num_seats);
    
    // 处理选座请求
    handle_reserve_seat_request(1, seats, num_seats);
    
    // 处理取消预约请求
    handle_cancel_reserve_request(1, seats, num_seats);
    
    // 处理落座请求
    handle_occupy_seat_request(1, seats, num_seats);
    
    return 0;
}

以上代码可以实现基本的人机交互功能，你可以根据实际需求进行修改和完善。同时，你还需要使用HTTP请求和响应来与网页前端进行通信，使用数据库来存储座位信息和用户的预约状态。