编程序实现下述磁盘调度算法,并求出每种算法的平均寻道长度，要求设计主界面以灵活选择某算法，且以下算法都要实现：

1、先来先服务算法（FCFS）

2、最短寻道时间优先算法（SSTF）

3、扫描算法（SCAN）

4、循环扫描算法（CSCAN）

-Programmed to achieve the following disk scheduling algorithm, and calculated for each algorithm the average seek length, the main interface to design a flexible choice of a certain algorithm, and must realize the following algorithm: 1, first-come first-serve algorithm (FCFS) 2, Shortest Seek Time priority algorithms (SSTF) 3, scan algorithm (SCAN) 4, cycle scan algorithm (CSCAN)