用C语言编写Cscan算法、look调度算法、Clook调度算法

1. C语言实现Cscan算法：

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#define MAX 100

void sort(int n, int arr[]) {
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n - i - 1; j++) {
            if (arr[j] > arr[j + 1]) {
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

int main() {
    int n, head, i, j, seek_time = 0, max, disk[MAX], left[MAX], right[MAX];

    printf("Enter the number of disk requests: ");
    scanf("%d", &n);

    printf("Enter the requests: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &disk[i]);
    }

    printf("Enter the initial head position: ");
    scanf("%d", &head);

    // Divide the requests into left and right of the head
    int left_cnt = 0, right_cnt = 0;
    for (i = 0; i < n; i++) {
        if (disk[i] < head) {
            left[left_cnt++] = disk[i];
        } else {
            right[right_cnt++] = disk[i];
        }
    }

    // Sort the left and right requests in ascending order
    sort(left_cnt, left);
    sort(right_cnt, right);

    // Calculate seek time
    for (i = 0; i < 2; i++) {
        if (i == 0) {
            max = left[left_cnt - 1];
            for (j = left_cnt - 2; j >= 0; j--) {
                seek_time += abs(max - left[j]);
                max = left[j];
            }
            seek_time += max - 0;
        } else {
            max = right[0];
            for (j = 1; j < right_cnt; j++) {
                seek_time += abs(max - right[j]);
                max = right[j];
            }
            seek_time += 199 - max;
        }
    }

    printf("Total seek time: %d\n", seek_time);

    return 0;
}

2. C语言实现look调度算法：

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#define MAX 100

void sort(int n, int arr[]) {
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n - i - 1; j++) {
            if (arr[j] > arr[j + 1]) {
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

int main() {
    int n, head, i, j, seek_time = 0, max, disk[MAX];

    printf("Enter the number of disk requests: ");
    scanf("%d", &n);

    printf("Enter the requests: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &disk[i]);
    }

    printf("Enter the initial head position: ");
    scanf("%d", &head);

    // Sort the requests in ascending order
    sort(n, disk);

    // Find the index of the head position in the requests
    int index = 0;
    for (i = 0; i < n; i++) {
        if (disk[i] == head) {
            index = i;
            break;
        }
    }

    // Move the head from the initial position towards the end
    for (i = index; i < n - 1; i++) {
        seek_time += abs(disk[i + 1] - disk[i]);
    }

    // If there are requests after the head position, move the head to the last request
    if (index != n - 1) {
        seek_time += abs(disk[n - 1] - disk[index]);
    }

    // Move the head from the last request towards the beginning
    for (i = n - 1; i > 0; i--) {
        seek_time += abs(disk[i] - disk[i - 1]);
    }

    printf("Total seek time: %d\n", seek_time);

    return 0;
}

3. C语言实现Clook调度算法：

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#define MAX 100

void sort(int n, int arr[]) {
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n - i - 1; j++) {
            if (arr[j] > arr[j + 1]) {
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

int main() {
    int n, head, i, j, seek_time = 0, max, disk[MAX], left[MAX], right[MAX];

    printf("Enter the number of disk requests: ");
    scanf("%d", &n);

    printf("Enter the requests: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &disk[i]);
    }

    printf("Enter the initial head position: ");
    scanf("%d", &head);

    // Divide the requests into left and right of the head
    int left_cnt = 0, right_cnt = 0;
    for (i = 0; i < n; i++) {
        if (disk[i] < head) {
            left[left_cnt++] = disk[i];
        } else {
            right[right_cnt++] = disk[i];
        }
    }

    // Sort the left and right requests in ascending order
    sort(left_cnt, left);
    sort(right_cnt, right);

    // Calculate seek time
    max = right[0];
    for (i = 1; i < right_cnt; i++) {
        seek_time += abs(max - right[i]);
        max = right[i];
    }
    seek_time += abs(max - left[0]);
    max = left[0];
    for (i = 1; i < left_cnt; i++) {
        seek_time += abs(max - left[i]);
        max = left[i];
    }

    printf("Total seek time: %d\n", seek_time);

    return 0;
}