scan_disk.c

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int RQ[100],path[100],i,j,k=0,n,TotalHeadMoment=0,initial,size,move;
    printf("Enter the number of Requests\n");
    scanf("%d",&n);
    printf("Enter the Requests sequence\n");
    for(i=0;i<n;i++)
     scanf("%d",&RQ[i]);
    printf("Enter initial head position\n");
    scanf("%d",&initial);
    printf("Enter total disk size\n");
    scanf("%d",&size);
    printf("Enter the head movement direction for high 1 and for low 0\n");
    scanf("%d",&move);
    
    // logic for Scan disk scheduling
    
        /*logic for sort the request array */
    for(i=0;i<n;i++)
    {
        for(j=0;j<n-i-1;j++)
        {
            if(RQ[j]>RQ[j+1])
            {
                int temp;
                temp=RQ[j];
                RQ[j]=RQ[j+1];
                RQ[j+1]=temp;
            }

        }
    }

    int index;
    for(i=0;i<n;i++)
    {
        if(initial<RQ[i])
        {
            index=i;
            break;
        }
    }
   
    // if movement is towards high value
    if(move==1)
    {
        for(i=index;i<n;i++)
        {
            TotalHeadMoment=TotalHeadMoment+abs(RQ[i]-initial);
            path[k]=RQ[i];
            initial=RQ[i];
            k++;
        }
        //  last movement for max size 
        TotalHeadMoment=TotalHeadMoment+abs(size-RQ[i-1]-1);
        path[k++]=size-1;
        initial = size-1;
        for(i=index-1;i>=0;i--)
        {
             TotalHeadMoment=TotalHeadMoment+abs(RQ[i]-initial);
             path[k]=RQ[i];
            initial=RQ[i];
            k++;
        }
    }
    // if movement is towards low value
    else
    {
        for(i=index-1;i>=0;i--)
        {
            TotalHeadMoment=TotalHeadMoment+abs(RQ[i]-initial);
            path[k]=RQ[i];
            initial=RQ[i];
            k++;
        }
        //  last movement for min size 
        TotalHeadMoment=TotalHeadMoment+abs(RQ[i+1]-0);
        path[k++]=0;
        initial =0;
        for(i=index;i<n;i++)
        {
             TotalHeadMoment=TotalHeadMoment+abs(RQ[i]-initial);
             path[k]=RQ[i];
            initial=RQ[i];
            k++;
        }
    }
    
    printf("Total head movement is %d\n",TotalHeadMoment);
    for(i=0;i<k;i++)
        printf("%d ",path[i]);
    return 0;
}