磁盘调度算法Java代码，使用FCFS,CSCAN,SCAN,SSTF算法

下面是使用Java实现FCFS、CSCAN、SCAN、SSTF算法的磁盘调度代码：

import java.util.*;

public class DiskScheduling {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the head position: ");
        int head = sc.nextInt();
        System.out.print("Enter the number of disk requests: ");
        int n = sc.nextInt();
        int[] requests = new int[n];
        System.out.println("Enter the disk requests: ");
        for (int i = 0; i < n; i++) {
            requests[i] = sc.nextInt();
        }

        // FCFS
        int[] fcfsSequence = new int[n + 1];
        fcfsSequence[0] = head;
        for (int i = 0; i < n; i++) {
            fcfsSequence[i + 1] = requests[i];
        }
        System.out.println("FCFS: " + Arrays.toString(fcfsSequence));

        // CSCAN
        int[] cscanSequence = new int[n + 2];
        cscanSequence[0] = head;
        cscanSequence[n + 1] = 0;
        int[] cscanRequests = new int[n + 2];
        cscanRequests[0] = head;
        cscanRequests[n + 1] = 0;
        for (int i = 0; i < n; i++) {
            cscanRequests[i + 1] = requests[i];
        }
        Arrays.sort(cscanRequests);
        int index = Arrays.binarySearch(cscanRequests, head);
        if (index < 0) {
            index = -index - 1;
        }
        int j = 1;
        for (int i = index; i <= n + 1; i++, j++) {
            cscanSequence[j] = cscanRequests[i];
        }
        for (int i = 1; i < index; i++, j++) {
            cscanSequence[j] = cscanRequests[i];
        }
        System.out.println("CSCAN: " + Arrays.toString(cscanSequence));

        // SCAN
        int[] scanSequence = new int[n + 1];
        scanSequence[0] = head;
        int[] scanRequests = new int[n + 1];
        for (int i = 0; i < n; i++) {
            scanRequests[i] = requests[i];
        }
        Arrays.sort(scanRequests);
        index = Arrays.binarySearch(scanRequests, head);
        if (index < 0) {
            index = -index - 1;
        }
        int i = index - 1, j = index + 1, k = 1;
        while (i >= 0 && j < n) {
            if (head - scanRequests[i] < scanRequests[j] - head) {
                scanSequence[k++] = scanRequests[i--];
            } else {
                scanSequence[k++] = scanRequests[j++];
            }
        }
        while (i >= 0) {
            scanSequence[k++] = scanRequests[i--];
        }
        while (j < n) {
            scanSequence[k++] = scanRequests[j++];
        }
        System.out.println("SCAN: " + Arrays.toString(scanSequence));

        // SSTF
        int[] sstfSequence = new int[n + 1];
        sstfSequence[0] = head;
        int[] sstfRequests = new int[n];
        for (int x = 0; x < n; x++) {
            sstfRequests[x] = requests[x];
        }
        for (int x = 0; x < n; x++) {
            int min = Integer.MAX_VALUE;
            int minIndex = -1;
            for (int y = 0; y < n - x; y++) {
                if (Math.abs(head - sstfRequests[y]) < min) {
                    min = Math.abs(head - sstfRequests[y]);
                    minIndex = y;
                }
            }
            sstfSequence[x + 1] = sstfRequests[minIndex];
            head = sstfRequests[minIndex];
            sstfRequests[minIndex] = sstfRequests[n - x - 1];
        }
        System.out.println("SSTF: " + Arrays.toString(sstfSequence));
    }
}

这个程序实现了FCFS、CSCAN、SCAN、SSTF算法的磁盘调度。用户可以输入磁头的初始位置、磁盘请求的数量和请求的位置。程序使用不同的算法对磁盘进行扫描，并输出磁头访问的顺序。其中，FCFS算法按照请求的顺序进行扫描；CSCAN算法按照磁头移动的方向扫描磁盘，并在两端循环；SCAN算法按照磁头移动的方向扫描磁盘，直到到达最边缘，然后返回扫描另一侧的磁盘；SSTF算法选择最近的磁盘访问。