# round robin scheduling algorithm program in java

- Round robin Scheduling algorithm (RR) is designed especially for time sharing system.It is similar to FCFS scheduling,but preempted is added to switch between processes.A small unit of time called a time quantum is defined.a time quantum is generally from 10 to 100 milliseconds.The CPU scheduler goes around the ready queue ,allocating the CPU to each process for a time interval of up to 1 time quantum.
**Input of Round robin Scheduling algorithm (RR) is:**

n=number of processes

bt[] =burst time array

wt[] =waiting time array

tat[] =turn around time array

sum = is used for addition of bt,wt,tat

a[] = is used for maintain original burst time before calculations.

**Output of Round robin Scheduling algorithm (RR) is:**

float avg_wt =average waiting time

float avg_tat =Average turn around time

### ROUND ROBIN SCHEDULING ALGORITHM Program:

```
import java.io. * ;
class round {
public static void main(String args[]) throws IOException {
DataInputStream in =new DataInputStream(System. in );
int i,
j,
k,
q,
sum = 0;
System.out.println("Enter number of process:");
int n = Integer.parseInt( in .readLine());
int bt[] = new int[n];
int wt[] = new int[n];
int tat[] = new int[n];
int a[] = new int[n];
System.out.println("Enter brust Time:");
for (i = 0; i < n; i++) {
System.out.println("Enter brust Time for " + (i + 1));
bt[i] = Integer.parseInt( in .readLine());
}
System.out.println("Enter Time quantum:");
q = Integer.parseInt( in .readLine());
for (i = 0; i < n; i++)
a[i] = bt[i];
for (i = 0; i < n; i++) {
wt[i] = 0;
}
do {
for (i = 0; i < n; i++) {
if (bt[i] > q) {
bt[i] -= q;
for (j = 0; j < n; j++) {
if ((j != i) && (bt[j] != 0)) wt[j] += q;
}
} else {
for (j = 0; j < n; j++) {
if ((j != i) && (bt[j] != 0)) wt[j] += bt[i];
}
bt[i] = 0;
}
}
sum = 0;
for (k = 0; k < n; k++)
sum = sum + bt[k];
}
while ( sum != 0 );
for (i = 0; i < n; i++) {
tat[i] = wt[i] + a[i];
}
System.out.println("process\t\tBT\tWT\tTAT");
for (i = 0; i < n; i++) {
System.out.println("process" + (i + 1) + "\t" + a[i] + "\t" + wt[i] + "\t" + tat[i]);
}
float avg_wt = 0;
float avg_tat = 0;
for (j = 0; j < n; j++) {
avg_wt += wt[j];
}
for (j = 0; j < n; j++) {
avg_tat += tat[j];
}
System.out.println("average waiting time " + (avg_wt / n) + "\n Average turn around time" + (avg_tat / n));
}
}
```

/***Round robin Scheduling algorithm output:**

Enter number of process:

4

Enter brust Time:

Enter brust Time for 1

4

Enter brust Time for 2

5

Enter brust Time for 3

6

Enter brust Time for 4

7

Enter Time quantum:

4

process BT WT TAT

process1 4 0 4

process2 5 12 17

process3 6 13 19

process4 7 15 22

average waiting time 10.0

Average turn around time15.5

*/

Download “round-robin.txt” round-robin.txt – Downloaded 309 times – 1 KB

:-*

Your code is not properly organized .

you are right.

variables are not properly named .