用程序模拟磁盘的调度过程，并计算各磁盘调度算法包括先来先服务算法、最短寻道时间优先算法、扫描算法和循环扫描算法的平均寻道长度

好的，我可以提供一些思路和伪代码供你参考。

首先，需要定义磁盘调度算法的数据结构，包括磁盘请求队列、当前磁头位置和寻道方向等信息。然后，可以根据不同的算法实现相应的调度函数。

以下是伪代码示例：

// 定义磁盘请求结构体
typedef struct {
    int track; // 磁道号
    int time; // 提交时间
} Request;

// 定义磁盘调度算法结构体
typedef struct {
    Request queue[MAX_REQUESTS]; // 磁盘请求队列
    int head; // 当前磁头位置
    int direction; // 寻道方向，1表示向外，-1表示向内
    int count; // 请求计数器
    double total_distance; // 总寻道距离
} Scheduler;

// 先来先服务算法
void fcfs(Scheduler* scheduler, Request request) {
    // 将请求加入队列尾部
    scheduler->queue[scheduler->count++] = request;
    // 计算寻道距离
    int distance = abs(request.track - scheduler->head);
    scheduler->total_distance += distance;
    // 更新磁头位置
    scheduler->head = request.track;
}

// 最短寻道时间优先算法
void sstf(Scheduler* scheduler, Request request) {
    // 将请求加入队列尾部
    scheduler->queue[scheduler->count++] = request;
    // 找到距离最近的请求
    int min_distance = INT_MAX;
    int min_index = -1;
    for (int i = 0; i < scheduler->count; i++) {
        int distance = abs(scheduler->queue[i].track - scheduler->head);
        if (distance < min_distance) {
            min_distance = distance;
            min_index = i;
        }
    }
    // 计算寻道距离
    scheduler->total_distance += min_distance;
    // 更新磁头位置
    scheduler->head = scheduler->queue[min_index].track;
    // 将请求移到队列头部
    Request temp = scheduler->queue[min_index];
    for (int i = min_index; i > 0; i--) {
        scheduler->queue[i] = scheduler->queue[i - 1];
    }
    scheduler->queue[0] = temp;
}

// 扫描算法
void scan(Scheduler* scheduler, Request request) {
    // 将请求加入队列尾部
    scheduler->queue[scheduler->count++] = request;
    // 排序请求队列
    for (int i = 0; i < scheduler->count - 1; i++) {
        for (int j = i + 1; j < scheduler->count; j++) {
            if (scheduler->queue[i].track > scheduler->queue[j].track) {
                Request temp = scheduler->queue[i];
                scheduler->queue[i] = scheduler->queue[j];
                scheduler->queue[j] = temp;
            }
        }
    }
    // 计算寻道距离
    int distance = 0;
    int index = 0;
    while (index < scheduler->count && scheduler->queue[index].track < scheduler->head) {
        distance += abs(scheduler->queue[index].track - scheduler->head);
        scheduler->head = scheduler->queue[index].track;
        index++;
    }
    if (index < scheduler->count && scheduler->queue[index].track == scheduler->head) {
        index++;
    }
    while (index < scheduler->count) {
        distance += abs(scheduler->queue[index].track - scheduler->head);
        scheduler->head = scheduler->queue[index].track;
        index++;
    }
    scheduler->total_distance += distance;
}

// 循环扫描算法
void cscan(Scheduler* scheduler, Request request) {
    // 将请求加入队列尾部
    scheduler->queue[scheduler->count++] = request;
    // 排序请求队列
    for (int i = 0; i < scheduler->count - 1; i++) {
        for (int j = i + 1; j < scheduler->count; j++) {
            if (scheduler->queue[i].track > scheduler->queue[j].track) {
                Request temp = scheduler->queue[i];
                scheduler->queue[i] = scheduler->queue[j];
                scheduler->queue[j] = temp;
            }
        }
    }
    // 计算寻道距离
    int distance = 0;
    int index = 0;
    while (index < scheduler->count && scheduler->queue[index].track < scheduler->head) {
        distance += abs(scheduler->queue[index].track - scheduler->head);
        scheduler->head = scheduler->queue[index].track;
        index++;
    }
    if (index < scheduler->count && scheduler->queue[index].track == scheduler->head) {
        index++;
    }
    if (index == scheduler->count) { // 如果已经扫描到队列末尾
        distance += abs(scheduler->queue[0].track - scheduler->head);
        scheduler->head = scheduler->queue[0].track;
        index = 0;
    }
    while (index < scheduler->count) {
        distance += abs(scheduler->queue[index].track - scheduler->head);
        scheduler->head = scheduler->queue[index].track;
        index++;
    }
    scheduler->total_distance += distance;
}

// 计算平均寻道长度
double average_distance(Scheduler* scheduler) {
    return scheduler->total_distance / scheduler->count;
}

// 主函数
int main() {
    Scheduler scheduler;
    scheduler.head = 50; // 假设初始磁头位置为50
    scheduler.direction = 1; // 假设初始寻道方向向外
    scheduler.count = 0;
    scheduler.total_distance = 0.0;

    // 读取磁盘请求，调用相应的调度算法
    while (has_request()) {
        Request request = read_request();
        if (scheduler.direction == 1) {
            if (request.track >= scheduler.head) {
                fcfs(&scheduler, request);
            } else {
                scheduler.direction = -1;
                scan(&scheduler, request);
            }
        } else {
            if (request.track <= scheduler.head) {
                fcfs(&scheduler, request);
            } else {
                scheduler.direction = 1;
                cscan(&scheduler, request);
            }
        }
    }

    // 输出平均寻道长度
    printf("FCFS: %lf\n", average_distance(&scheduler));
    // 重新初始化调度算法结构体
    scheduler.head = 50;
    scheduler.direction = 1;
    scheduler.count = 0;
    scheduler.total_distance = 0.0;
    // 读取磁盘请求，调用相应的调度算法
    while (has_request()) {
        Request request = read_request();
        sstf(&scheduler, request);
    }
    // 输出平均寻道长度
    printf("SSTF: %lf\n", average_distance(&scheduler));
    // 重新初始化调度算法结构体
    scheduler.head = 50;
    scheduler.direction = 1;
    scheduler.count = 0;
    scheduler.total_distance = 0.0;
    // 读取磁盘请求，调用相应的调度算法
    while (has_request()) {
        Request request = read_request();
        scan(&scheduler, request);
    }
    // 输出平均寻道长度
    printf("SCAN: %lf\n", average_distance(&scheduler));
    // 重新初始化调度算法结构体
    scheduler.head = 50;
    scheduler.direction = 1;
    scheduler.count = 0;
    scheduler.total_distance = 0.0;
    // 读取磁盘请求，调用相应的调度算法
    while (has_request()) {
        Request request = read_request();
        cscan(&scheduler, request);
    }
    // 输出平均寻道长度
    printf("CSCAN: %lf\n", average_distance(&scheduler));
    return 0;
}

需要注意的是，以上代码仅为伪代码示例，实际实现中需要考虑更多细节和异常情况。