Write a simulation program for scheduling algorithm using FCFS. The arrival time and first CPU burst of different jobs should be input to the system. The output should give the Gantt chart & turnaround time for each process and average turnaround time.

Write a simulation program for scheduling algorithm using FCFS. The arrival time and first CPU burst of different jobs should be input to the system. The output should give the Gantt chart & turnaround time for each process and average turnaround time.

Program:

#include <stdio.h>
#include <stdlib.h>

struct sch{
 int at,st,bt,tat,ft;
}pr[50];

int rq[50],x,n,timer;
void addP(){
 int i;
 for(i=0;i<n;i++){
  if(pr[i].at==timer){
   rq[x++]=i;
  }
 }
}
int selectP(){
 int pp,i;
 if(x<0){
  return(-1);
 }else{
  pp=rq[0];
  for(i=0;i<n;i++){
   rq[i]=rq[i+1];
  }
  x--;
  return(pp);
 }
}

int main(void){
 setbuf(stdout,NULL);
 int i,t,p;
 float atat;
 timer = 0;
 x=-1;
 printf("Enter the number of processes:");
 scanf("%d",&n);
 for(i=0;i<n;i++){
  printf("\nEnter the Arrival time:");
  scanf("%d",&pr[i].at);
  printf("\nEnter the Burst time:");
  scanf("%d",&pr[i].bt);
 }
 t=0;
 addP();
 while(t<n){
  p=selectP();
  if(p==-1){
   printf("idle|");
   timer++;
   addP();
  }else{
   pr[p].st=timer;
   for(i=0;i<pr[p].bt;i++){
    printf("P%d|",p);
    timer++;
    addP();
   }
   pr[p].ft=pr[p].st+pr[p].bt;
   t++;
  }
 }
 atat=0;
 printf("\nTurn Around Time for each Process:");
 for(i=0;i<n;i++){
  pr[i].tat = pr[i].ft-pr[i].at;
  printf("\nP%d=%d",i,pr[i].tat);
  atat+=pr[i].tat;
 }
 atat = atat/n;
 printf("\nAverage Turn Around Time:%f",atat);
 return EXIT_SUCCESS;
}