请写一段完整的，有FCFS,SSTF,SCAN,CSCAN算法的磁盘调度程序

好的，以下是一个基于Python语言实现的磁盘调度程序，其中包含FCFS、SSTF、SCAN和CSCAN四种算法：

import heapq

# 定义磁盘请求队列
requests = [98, 183, 37, 122, 14, 124, 65, 67]
start = 53

# FCFS算法
def fcfs(requests, start):
    total_movement = 0
    current = start
    for request in requests:
        total_movement += abs(current - request)
        current = request
    return total_movement

# SSTF算法
def sstf(requests, start):
    total_movement = 0
    current = start
    while len(requests) > 0:
        distances = [abs(current - request) for request in requests]
        index = distances.index(min(distances))
        total_movement += min(distances)
        current = requests.pop(index)
    return total_movement

# SCAN算法
def scan(requests, start):
    total_movement = 0
    current = start
    # 找到最大请求和最小请求
    max_request = max(requests)
    min_request = min(requests)
    # 确定扫描方向
    if current < min_request:
        direction = 1
        requests.append(max_request)
    else:
        direction = -1
        requests.append(min_request)
    # 进行扫描
    while current != requests[0]:
        current += direction
    while len(requests) > 0:
        request = requests.pop(0)
        total_movement += abs(current - request)
        current = request
    return total_movement

# CSCAN算法
def cscan(requests, start):
    total_movement = 0
    current = start
    # 找到最大请求和最小请求
    max_request = max(requests)
    min_request = min(requests)
    # 确定扫描方向
    if current < min_request:
        direction = 1
        requests.append(max_request)
        requests.append(0)
    else:
        direction = -1
        requests.append(min_request)
        requests.append(max_request)
    # 进行扫描
    while current != requests[0]:
        current += direction
    while len(requests) > 0:
        request = requests.pop(0)
        total_movement += abs(current - request)
        current = request
    return total_movement

# 输出各种算法的结果
print("FCFS algorithm: ", fcfs(requests, start))
print("SSTF algorithm: ", sstf(requests, start))
print("SCAN algorithm: ", scan(requests, start))
print("CSCAN algorithm: ", cscan(requests, start))

以上程序中，我们定义了一个磁盘请求队列requests和起始位置start，并分别实现了FCFS、SSTF、SCAN和CSCAN四种算法。我们可以根据具体情况选择不同的算法来进行磁盘调度。