Roundrobin.c

#include<stdio.h>
struct process{
int id,at,bt,ct,tat,wt,status,rt,qstatus;
};
int q[100],front=-1,rear=-1;
void enqueue(int item)
{
if((front==-1)&&(rear==-1))
{
front=0;
rear=0;
q[rear]=item;
}
else
{
rear++;
q[rear]=item;
}
}
int dequeue()
{
int item;
if(front==rear)
{
item=q[front];
front=-1;
rear=-1;
}
else
{
item=q[front];
front++;
}
return(item);
}

void main()
{
struct process p[100];
float tot_tat=0,avg_tat,tot_wt=0,avg_wt;
int j,i,n,completed=0,current_time=0,time;
printf("enter number of process\n");
scanf("%d",&n);
printf("enter process details\n");
for(i=0;i<=n-1;i++)
{
printf("enter the id \t arrival time \t burst time\n");
scanf("%d%d%d",&p[i].id,&p[i].at,&p[i].bt);
p[i].rt=p[i].bt;
p[i].status=0;
p[i].qstatus=0;
}
printf("enter the time quantum\n");
scanf("%d",&time);

current_time=p[0].at;
enqueue(0);
p[0].qstatus=1;

while(completed!=n)
{
i=dequeue();
if(p[i].rt==time)
{
current_time=current_time+time;
p[i].ct=current_time;
p[i].rt=0;
p[i].status=1;
completed++;
}
else if(p[i].rt<time)
{
current_time=current_time+p[i].rt;
p[i].ct=current_time;
p[i].rt=0;
p[i].status=1;
completed++;
}
else
{
current_time=current_time+time;
p[i].rt=p[i].rt-time;
}
for(j=i+1;j<n;j++)
{
if((p[j].at<=current_time)&&(p[j].status==0)&&(p[j].qstatus==0))
{
enqueue(j);
p[j].qstatus=1;
}
}
if(p[i].rt!=0)
{
enqueue(i);
}
}
for(i=0;i<n;i++)
{
p[i].tat=p[i].ct-p[i].at;
tot_tat=tot_tat+p[i].tat;
p[i].wt=p[i].tat-p[i].bt;
tot_wt=tot_wt+p[i].wt;
}
avg_tat=tot_tat/n;
avg_wt=tot_wt/n;

printf("id\tat\tbt\tct\ttat\twt\n");
for(i=0;i<n;i++)
{
printf("%d\t%d\t%d\t%d\t%d\t%d\n",p[i].id,p[i].at,p[i].bt,p[i].ct,p[i].tat,p[i].wt);
}
printf("average tat is %f",avg_tat);
printf("average wt is %f",avg_wt);
}