常见磁盘调度算法的源代码

以下是常见磁盘调度算法的源代码示例：

1. 先来先服务 (FCFS)

#include<stdio.h>
#include<conio.h>
void main()
{
    int n,a[10],i,d=0;
    printf("Enter the number of requests:");
    scanf("%d",&n);
    printf("Enter the requests:");
    for(i=0;i<n;i++)
        scanf("%d",&a[i]);
    printf("Seek Sequence is:");
    for(i=0;i<n;i++)
    {
        printf("%d ",a[i]);
        d+=abs(a[i]-a[i-1]);
    }
    printf("\nTotal Seek Time is %d",d);
    getch();
}

2. 最短寻道时间优先 (SSTF)

#include<stdio.h>
#include<conio.h>
void main()
{
    int n,a[10],i,j,min,d=0,k=0,b[10],c[10],flag[10]={0};
    printf("Enter the number of requests:");
    scanf("%d",&n);
    printf("Enter the requests:");
    for(i=0;i<n;i++)
        scanf("%d",&a[i]);
    for(i=0;i<n;i++)
    {
        min=1000;
        for(j=0;j<n;j++)
        {
            if(flag[j]==0)
            {
                if(min>abs(a[j]-k))
                {
                    min=abs(a[j]-k);
                    b[i]=a[j];
                    c[i]=j;
                }
            }
        }
        flag[c[i]]=1;
        k=b[i];
        d+=min;
    }
    printf("Seek Sequence is:");
    for(i=0;i<n;i++)
        printf("%d ",b[i]);
    printf("\nTotal Seek Time is %d",d);
    getch();
}

3. 扫描算法 (SCAN)

#include<stdio.h>
#include<conio.h>
void main()
{
    int n,a[10],i,j,temp,d=0,k,pos;
    printf("Enter the number of requests:");
    scanf("%d",&n);
    printf("Enter the requests:");
    for(i=0;i<n;i++)
        scanf("%d",&a[i]);
    printf("Enter the initial position:");
    scanf("%d",&k);
    for(i=0;i<n-1;i++)
    {
        for(j=i+1;j<n;j++)
        {
            if(a[i]>a[j])
            {
                temp=a[i];
                a[i]=a[j];
                a[j]=temp;
            }
        }
    }
    for(i=0;i<n;i++)
    {
        if(a[i]>k)
        {
            pos=i;
            break;
        }
    }
    printf("Seek Sequence is:");
    if(k<=50)
    {
        for(i=pos;i<n;i++)
        {
            printf("%d ",a[i]);
            d+=abs(a[i]-k);
            k=a[i];
        }
        d+=abs(199-k);
        k=199;
        for(i=pos-1;i>=0;i--)
        {
            printf("%d ",a[i]);
            d+=abs(a[i]-k);
            k=a[i];
        }
    }
    else
    {
        for(i=pos-1;i>=0;i--)
        {
            printf("%d ",a[i]);
            d+=abs(a[i]-k);
            k=a[i];
        }
        d+=abs(0-k);
        k=0;
        for(i=pos;i<n;i++)
        {
            printf("%d ",a[i]);
            d+=abs(a[i]-k);
            k=a[i];
        }
    }
    printf("\nTotal Seek Time is %d",d);
    getch();
}

4. 循环扫描算法 (C-SCAN)

#include<stdio.h>
#include<conio.h>
void main()
{
    int n,a[10],i,j,temp,d=0,k,pos;
    printf("Enter the number of requests:");
    scanf("%d",&n);
    printf("Enter the requests:");
    for(i=0;i<n;i++)
        scanf("%d",&a[i]);
    printf("Enter the initial position:");
    scanf("%d",&k);
    for(i=0;i<n-1;i++)
    {
        for(j=i+1;j<n;j++)
        {
            if(a[i]>a[j])
            {
                temp=a[i];
                a[i]=a[j];
                a[j]=temp;
            }
        }
    }
    for(i=0;i<n;i++)
    {
        if(a[i]>k)
        {
            pos=i;
            break;
        }
    }
    printf("Seek Sequence is:");
    if(k<=50)
    {
        for(i=pos;i<n;i++)
        {
            printf("%d ",a[i]);
            d+=abs(a[i]-k);
            k=a[i];
        }
        d+=abs(199-k);
        k=199;
        for(i=0;i<pos;i++)
        {
            printf("%d ",a[i]);
            d+=abs(a[i]-k);
            k=a[i];
        }
        d+=abs(199-k);
    }
    else
    {
        for(i=pos-1;i>=0;i--)
        {
            printf("%d ",a[i]);
            d+=abs(a[i]-k);
            k=a[i];
        }
        d+=abs(0-k);
        k=0;
        for(i=n-1;i>=pos;i--)
        {
            printf("%d ",a[i]);
            d+=abs(a[i]-k);
            k=a[i];
        }
        d+=abs(0-k);
    }
    printf("\nTotal Seek Time is %d",d);
    getch();
}

5. 最高响应比优先 (HRRN)

#include<stdio.h>
#include<conio.h>
void main()
{
    int n,bt[10],wt[10],tat[10],i,j,sum=0,max,p[10];
    float avg_wt,avg_tat;
    printf("Enter the number of processes:");
    scanf("%d",&n);
    printf("Enter the burst time of processes:");
    for(i=0;i<n;i++)
    {
        scanf("%d",&bt[i]);
        p[i]=i+1;
    }
    wt[0]=0;
    for(i=1;i<n;i++)
    {
        wt[i]=0;
        for(j=0;j<i;j++)
            wt[i]+=bt[j];
        sum+=wt[i];
    }
    avg_wt=(float)sum/n;
    sum=0;
    printf("\nProcess\tBurst Time\tWaiting Time\tTurnaround Time");
    for(i=0;i<n;i++)
    {
        tat[i]=bt[i]+wt[i];
        sum+=tat[i];
        printf("\nP%d\t%d\t\t%d\t\t%d",p[i],bt[i],wt[i],tat[i]);
    }
    avg_tat=(float)sum/n;
    printf("\nAverage Waiting Time:%f",avg_wt);
    printf("\nAverage Turnaround Time:%f",avg_tat);
    max=0;
    for(i=0;i<n;i++)
    {
        if(max<((float)(bt[i]+wt[i])/bt[i]))
        {
            max=(float)(bt[i]+wt[i])/bt[i];
            j=i;
        }
    }
    printf("\nProcess with highest response ratio:P%d",p[j]);
    getch();
}