FCFS CPU Scheduling Algorithm

#include<stdio.h>
#include<conio.h>
#define max 10

int i,nop;

struct process
{
 int prn;
 int bt;
 int wt;
 int tt;
}pr[max];

void ins_dat()
{
 for(i=0;i<nop;i++)
 {
  pr[i].prn = i+1;
  printf("\n Enter the Burst time of Process #%d : ",pr[i].prn);
  scanf("%d",&pr[i].bt);
 }
}

void FCFS()
{
 for(i=0;i<nop;i++)
 {
  pr[i].wt = pr[i].prn == 1 ? 0 : pr[i-1].tt ;
  pr[i].tt = pr[i].wt + pr[i].bt;
 }
}

void disp_dat()
{
 int ttl_tt=0,ttl_wt=0;
 float avg_tt,avg_wt;
 printf("\n\n Process   Waiting Time   Burst Time   Turnaround Time \n");
 printf(" ------------------------------------------------------- \n");
 for(i=0;i<nop;i++)
 {
  printf(" %d \t\t %d \t\t %d \t\t %d\n\n",pr[i].prn,pr[i].wt,pr[i].bt,pr[i].tt);
  ttl_wt += pr[i].wt;
  ttl_tt += pr[i].tt;
 }
 avg_wt = (float) ttl_wt/nop;
 avg_tt = (float) ttl_tt/nop;
 printf("\n\n Average Waiting Time  : %f",avg_wt);
 printf("\n Average Turnaround Time : %f",avg_tt);
}

void main()
{
 do
 {

 printf("\n Enter the number of processes : ");
 scanf("%d",&nop);
 }while(nop > max || nop <= 0);
 ins_dat();
 FCFS();
 disp_dat();
 getch();
}