Implement the Round Robin scheduling for, Given the list of processes, their CPU burst times and arrival times, print the Gantt chart for RR and also compute and print the average waiting time and average turnaround time.

#include<stdio.h>

main()

{

int pt[10][10],a[10][10],at[10],pname[10][10],i,j,n,k=0,q,sum=0;

float avg;

printf("\n\n Enter the number of processes : "); scanf("%d",&n);

for(i=0;i<10;i++)

{

for(j=0;j<10;j++)


{

pt[i][j]=0;

a[i][j]=0;

}

}

for(i=0;i<n;i++)

{

j=0;

printf("\n\n Enter the process time for process %d : ",i+1); scanf("%d",&pt[i][j]);

}

printf("\n\n Enter the time slice : ");

scanf("%d",&q);

printf("\n\n");

for(j=0;j<10;j++)

{

for(i=0;i<n;i++)

{

a[2*j][i]=k;

if((pt[i][j]<=q)&&(pt[i][j]!=0))

{

pt[i][j+1]=0;

printf(" %d P%d %d\n",k,i+1,k+pt[i][j]); k+=pt[i][j];

a[2*j+1][i]=k;

}

else if(pt[i][j]!=0)

{

pt[i][j+1]=pt[i][j]-q;


printf(" %d P%d %d\n",k,i+1,(k+q)); k+=q;

a[2*j+1][i]=k;

}

else

{

a[2*j][i]=0;

a[2*j+1][i]=0;

}

}

}

for(i=0;i<n;i++)

sum+=a[0][i];

for(i=0;i<n;i++)

{

for(j=1;j<10;j++)

{

if((a[j][i]!=0)&&(a[j+1][i]!=0)&&((j+1)%2==0)) sum+=((a[j+1][i]-a[j][i]));

}

}

avg=(float)sum/n;

printf("\n\n Average waiting time = %f msec",avg); sum=avg=0;

for(j=0;j<n;j++)

{

i=1;

while(a[i][j]!=0)

i+=1; sum+=a[i-1][j];

}

avg=(float)sum/n;

printf("\n\n Average turnaround time = %f msec\n\n",avg);

}

OUTPUT:

Enter the number of processes : 4

Enter the process time for process 1 : 8
Enter the process time for process 2 : 3
Enter the process time for process 3 : 6
Enter the process time for process 4 : 1

Enter the time slice : 2

0 P1 2

2 P2 4

4 P3 6

6 P4 7

7 P1 9

9 P2 10

10 P3 12

12 P1 14

14 P3 16

16 P1 18

Average waiting time = 8.250000 msec
Average turnaround time = 12.750000 msec