SSTF Disk Scheduling Algorithm

#include<stdio.h>
#include<conio.h>
#include<limits.h>
#include<math.h>
#define max 20
#define cymax 199

int i,j,req,ttl_tracks=0,cp,np,cposn;
int cyposn[max],ind[max],temp;

void input()
{
 do
 {
  clreol();
  printf("\n Enter the current header position : ");
  scanf("%d",&cposn);
 }while(cposn>cymax || cposn <=0);
 printf("\n Enter the %d I/O Requests : ",req);
 cyposn[0] = cposn;
 for(i=1;i<=req;i++)
 {
  scanf("%d",&cyposn[i]);
  ind[i] = 0;
 }

}

void search_short()
{
 int npl,npr,tmpr,tmpl;
 if(cp == 0)
 {
  np = cp;
  while(ind[np] == 1 && np < req)
   np++;
 }
 else if(cp == req)
 {
  np = cp;
  while(ind[np] == 1 && np > 0)
   np--;
 }
 else
 {
  npl = cp;
  while(ind[npl] == 1 && npl > 0)
   npl--;
  if(npl == 0 && ind[npl] == 1)
   tmpl = INT_MAX;
  else
   tmpl = cyposn[npl];
  npr = cp;
  while(ind[npr] == 1 && npr < req)
   npr++;
  if(npl == req && ind[npr] == 1)
   tmpr = INT_MAX;
  else
   tmpr = cyposn[npr];
  if(abs(cyposn[cp] - tmpl) < abs(cyposn[cp] - tmpr))
   np = npl;
  else
   np = npr;
 }
 ind[np] = 1;
}

void SSTF()
{
 for(i=0;i<=req;i++)
 {
  for(j=0;j<req-i;j++)
  {
   if(cyposn[j] > cyposn[j+1])
   {
    temp = cyposn[j];
    cyposn[j] = cyposn[j+1];
    cyposn[j+1] = temp;
   }
  }
 }
 cp=0;
 do
 {
  if(cyposn[cp] == cposn)
   break;
  cp++;
 }while(cp!=req);
 ind[cp] = 1;
 printf("\nS.No.  Current Position    Next Position   Displacement \n");
 printf("---------------------------------------------------------- \n\n");
 i = 0 ;
 do
 {
  search_short();
  printf(" %d\t\t%d\t\t%d\t\t%d\t\t%d\n",i+1,cyposn[cp],cyposn[np],abs(cyposn[cp]-cyposn[np]),np);
  ttl_tracks += (abs(cyposn[cp]-cyposn[np]));
  cp = np;
  i++;
 }while(i!=req);
 printf("---------------------------------------------------------- \n\n");
 printf(" Total Tracks Displaced : %d",ttl_tracks);
}

void main()
{
 do
 {
  clrscr();
  printf("\n Enter the number of requests : ");
  scanf("%d",&req);
 }while(req>max || req <=0);
 input();
 SSTF();
 getch();
}