Q.2 Write a simulation program for disk scheduling using C-SCAN algorithm. Accept
total number of disk blocks, disk request string, and current head position from the user.
Display the list of request in the order in which it is served. Also display the total
number of head moments.
33, 99, 142, 52, 197, 79, 46, 65
Start Head Position: 72
Direction: Left

#include<stdio.h>
#include<stdlib.h>
int main()
{
int RQ[100],i,j,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);
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(move==1)
{
for(i=index;i<n;i++)
{
TotalHeadMoment=TotalHeadMoment+abs(RQ[i]-initial);
initial=RQ[i];
}
TotalHeadMoment=TotalHeadMoment+abs(size-RQ[i-1]-1);
TotalHeadMoment=TotalHeadMoment+abs(size-1-0);
initial=0;
for( i=0;i<index;i++)
{
TotalHeadMoment=TotalHeadMoment+abs(RQ[i]-initial);
initial=RQ[i];
}
}
else
{
for(i=index-1;i>=0;i--)
{
TotalHeadMoment=TotalHeadMoment+abs(RQ[i]-initial);
initial=RQ[i];
}
TotalHeadMoment=TotalHeadMoment+abs(RQ[i+1]-0);
TotalHeadMoment=TotalHeadMoment+abs(size-1-0);
initial =size-1;
for(i=n-1;i>=index;i--)
{
TotalHeadMoment=TotalHeadMoment+abs(RQ[i]-initial);
initial=RQ[i];}
}
printf("Total head movement is %d",TotalHeadMoment);
return 0;
}