Round Robin CPU Scheduling Algorithm (Pointers)

#include<stdio.h>
#include<conio.h>


int qt;

struct process
{
 int prn;
 int bt;
 int wt;
 int tt;
 struct process *nxt;
}*start,*np,*end,*temp;

void ins_node(struct process *np)
{
 if(start == NULL)
    start = end = np;
  else
  {
   end->nxt = np;
   end = np;
  }
}

void del_node(struct process *np,int choice)
{
  if(start == end)
   start = NULL;
  else
   start = start->nxt;
  if(choice == 1)
   delete np;
}

void ins_dat()
{
  char ch;
  int i=0;
  start = end = NULL;
  do
  {
  np = new process;
  np->nxt = NULL;
  np->prn = ++i;
  printf("\n Enter the Burst time of Process #%d : ",np->prn);
  scanf("%d",&np->bt);
  np->nxt = start;
  np->wt = np->tt = 0;
  ins_node(np);
  printf("\n\n Continue ?? : ");
  ch = getche();
  }while(ch == 'y');
}

void Round_Robin()
{
 float avg_wt,avg_tt;
 int i = 0,ttl_wt=0,ttl_tt=0;
 getch();
 printf("\n\n Process   Burst Time   Waiting Time   Turnaround Time \n");
 printf(" ------------------------------------------------------- \n");
 temp = start;
 do
 {
   printf(" %d \t\t %d \t\t",start->prn,start->bt);
   start->wt += (temp->tt - start->tt);
   if(qt >= start->bt)
   {
    start->tt = temp->tt + start->bt;
    start->bt = 0;
    printf(" %d \t\t %d\n\n",start->wt,start->tt);
    ttl_wt += start->wt;
    ttl_tt += start->tt;
    temp = np = start;
    del_node(np,1);
    ++i;
   }
   else
   {
    start->bt -= qt;
    start->tt = temp->tt + qt;
    printf(" %d \t\t %d\n\n",start->wt,start->tt);
    np = temp = start;
    del_node(np,2);
    ins_node(np);
   }
 }while(start != NULL);
    avg_wt = (float) ttl_wt/i;
    avg_tt = (float) ttl_tt/i;
   printf("\n\n Average Waiting Time  : %f",avg_wt);
   printf("\n Average Turnaround Time : %f",avg_tt);
}

void main()
{
 clrscr();
 printf("\n Enter the Quantum time : ");
 scanf("%d",&qt);
 ins_dat();
 Round_Robin();
 getch();
}