磁盘调度5个算法代码C语言

以下是五种磁盘调度算法的 C 语言示例代码：

1. 先来先服务算法（FCFS）

#include<stdio.h>
#include<stdlib.h>
 
int main()
{
    int n,i,j,k,head,seek=0,diff;
    printf("Enter the number of requests : ");
    scanf("%d",&n);
    int req[n];
    printf("Enter the requests : ");
    for(i=0;i<n;i++)
        scanf("%d",&req[i]);
    printf("Enter the initial head position : ");
    scanf("%d",&head);
    printf("\nSeek Sequence : ");
    for(i=0;i<n;i++)
    {
        diff=abs(head-req[i]);
        seek+=diff;
        head=req[i];
        printf("%d ",req[i]);
    }
    printf("\nTotal Seek Time : %d",seek);
    return 0;
}

2. 最短寻道时间优先算法（SSTF）

#include<stdio.h>
#include<stdlib.h>
 
int min(int a,int b)
{
    return a>b?b:a;
}
 
int main()
{
    int n,i,j,k,head,seek=0,diff,minn,index;
    printf("Enter the number of requests : ");
    scanf("%d",&n);
    int req[n],visited[n];
    printf("Enter the requests : ");
    for(i=0;i<n;i++)
    {
        visited[i]=0;
        scanf("%d",&req[i]);
    }
    printf("Enter the initial head position : ");
    scanf("%d",&head);
    printf("\nSeek Sequence : ");
    for(i=0;i<n;i++)
    {
        minn=1000000;
        for(j=0;j<n;j++)
        {
            if(visited[j]==0)
            {
                diff=abs(head-req[j]);
                if(diff<minn)
                {
                    minn=diff;
                    index=j;
                }
            }
        }
        visited[index]=1;
        seek+=minn;
        head=req[index];
        printf("%d ",req[index]);
    }
    printf("\nTotal Seek Time : %d",seek);
    return 0;
}

3. 扫描算法（SCAN）

#include<stdio.h>
#include<stdlib.h>
 
int main()
{
    int n,i,j,k,head,seek=0,diff,minn,index;
    printf("Enter the number of requests : ");
    scanf("%d",&n);
    int req[n],visited[n];
    printf("Enter the requests : ");
    for(i=0;i<n;i++)
    {
        visited[i]=0;
        scanf("%d",&req[i]);
    }
    printf("Enter the initial head position : ");
    scanf("%d",&head);
    printf("\nSeek Sequence : ");
    int left=0,right=199;
    for(i=head;i>=left;i--)
    {
        for(j=0;j<n;j++)
        {
            if(req[j]==i && visited[j]==0)
            {
                visited[j]=1;
                printf("%d ",req[j]);
                seek+=abs(head-req[j]);
                head=req[j];
            }
        }
    }
    printf("%d ",left);
    seek+=abs(head-left);
    head=left;
    for(i=left+1;i<=right;i++)
    {
        for(j=0;j<n;j++)
        {
            if(req[j]==i && visited[j]==0)
            {
                visited[j]=1;
                printf("%d ",req[j]);
                seek+=abs(head-req[j]);
                head=req[j];
            }
        }
    }
    printf("\nTotal Seek Time : %d",seek);
    return 0;
}

4. 循环扫描算法（C-SCAN）

#include<stdio.h>
#include<stdlib.h>
 
int main()
{
    int n,i,j,k,head,seek=0,diff,minn,index;
    printf("Enter the number of requests : ");
    scanf("%d",&n);
    int req[n],visited[n];
    printf("Enter the requests : ");
    for(i=0;i<n;i++)
    {
        visited[i]=0;
        scanf("%d",&req[i]);
    }
    printf("Enter the initial head position : ");
    scanf("%d",&head);
    printf("\nSeek Sequence : ");
    int left=0,right=199;
    for(i=head;i<=right;i++)
    {
        for(j=0;j<n;j++)
        {
            if(req[j]==i && visited[j]==0)
            {
                visited[j]=1;
                printf("%d ",req[j]);
                seek+=abs(head-req[j]);
                head=req[j];
            }
        }
    }
    for(i=left;i<head;i++)
    {
        for(j=0;j<n;j++)
        {
            if(req[j]==i && visited[j]==0)
            {
                visited[j]=1;
                printf("%d ",req[j]);
                seek+=abs(head-req[j]);
                head=req[j];
            }
        }
    }
    printf("%d ",right);
    seek+=abs(head-right);
    head=right;
    for(i=right-1;i>=head;i--)
    {
        for(j=0;j<n;j++)
        {
            if(req[j]==i && visited[j]==0)
            {
                visited[j]=1;
                printf("%d ",req[j]);
                seek+=abs(head-req[j]);
                head=req[j];
            }
        }
    }
    printf("\nTotal Seek Time : %d",seek);
    return 0;
}

5. 最短电梯优先算法（LOOK）

#include<stdio.h>
#include<stdlib.h>
 
int main()
{
    int n,i,j,k,head,seek=0,diff,minn,index;
    printf("Enter the number of requests : ");
    scanf("%d",&n);
    int req[n],visited[n];
    printf("Enter the requests : ");
    for(i=0;i<n;i++)
    {
        visited[i]=0;
        scanf("%d",&req[i]);
    }
    printf("Enter the initial head position : ");
    scanf("%d",&head);
    printf("\nSeek Sequence : ");
    int left=-1,right=n;
    for(i=0;i<n;i++)
    {
        if(req[i]<head)
            left=i;
        else
        {
            right=i;
            break;
        }
    }
    while(left>=0 || right<n)
    {
        if(left>=0 && right<n)
        {
            if(abs(head-req[left])<abs(head-req[right]))
            {
                printf("%d ",req[left]);
                seek+=abs(head-req[left]);
                head=req[left];
                left--;
            }
            else
            {
                printf("%d ",req[right]);
                seek+=abs(head-req[right]);
                head=req[right];
                right++;
            }
        }
        else if(left>=0)
        {
            printf("%d ",req[left]);
            seek+=abs(head-req[left]);
            head=req[left];
            left--;
        }
        else if(right<n)
        {
            printf("%d ",req[right]);
            seek+=abs(head-req[right]);
            head=req[right];
            right++;
        }
    }
    printf("\nTotal Seek Time : %d",seek);
    return 0;
}