Created roundr.java

roundr.java

@@ -0,0 +1,248 @@
+ Java program for implementation of RR scheduling
+
+
+public class GFG 
+{
+
+    // Method to find the waiting time for all
+
+    // processes
+
+    static void findWaitingTime(int processes[], int n,
+
+                 int bt[], int wt[], int quantum)
+
+    {
+
+        // Make a copy of burst times bt[] to store remaining
+
+        // burst times.
+
+        int rem_bt[] = new int[n];
+
+        for (int i = 0 ; i < n ; i++)
+
+            rem_bt[i] =  bt[i];
+
+
+
+        int t = 0; // Current time
+
+
+
+        // Keep traversing processes in round robin manner
+
+        // until all of them are not done.
+
+        while(true)
+
+        {
+
+            boolean done = true;
+
+
+
+            // Traverse all processes one by one repeatedly
+
+            for (int i = 0 ; i < n; i++)
+
+            {
+
+                // If burst time of a process is greater than 0
+
+                // then only need to process further
+
+                if (rem_bt[i] > 0)
+
+                {
+
+                    done = false; // There is a pending process
+
+
+
+                    if (rem_bt[i] > quantum)
+
+                    {
+
+                        // Increase the value of t i.e. shows
+
+                        // how much time a process has been processed
+
+                        t += quantum;
+
+
+
+                        // Decrease the burst_time of current process
+
+                        // by quantum
+
+                        rem_bt[i] -= quantum;
+
+                    }
+
+
+
+                    // If burst time is smaller than or equal to
+
+                    // quantum. Last cycle for this process
+
+                    else
+
+                    {
+
+                        // Increase the value of t i.e. shows
+
+                        // how much time a process has been processed
+
+                        t = t + rem_bt[i];
+
+
+
+                        // Waiting time is current time minus time
+
+                        // used by this process
+
+                        wt[i] = t - bt[i];
+
+
+
+                        // As the process gets fully executed
+
+                        // make its remaining burst time = 0
+
+                        rem_bt[i] = 0;
+
+                    }
+
+                }
+
+            }
+
+
+
+            // If all processes are done
+
+            if (done == true)
+
+              break;
+
+        }
+
+    }
+
+
+
+    // Method to calculate turn around time
+
+    static void findTurnAroundTime(int processes[], int n,
+
+                            int bt[], int wt[], int tat[])
+
+    {
+
+        // calculating turnaround time by adding
+
+        // bt[i] + wt[i]
+
+        for (int i = 0; i < n ; i++)
+
+            tat[i] = bt[i] + wt[i];
+
+    }
+
+
+
+    // Method to calculate average time
+
+    static void findavgTime(int processes[], int n, int bt[],
+
+                                         int quantum)
+
+    {
+
+        int wt[] = new int[n], tat[] = new int[n];
+
+        int total_wt = 0, total_tat = 0;
+
+
+
+        // Function to find waiting time of all processes
+
+        findWaitingTime(processes, n, bt, wt, quantum);
+
+
+
+        // Function to find turn around time for all processes
+
+        findTurnAroundTime(processes, n, bt, wt, tat);
+
+
+
+        // Display processes along with all details
+
+        System.out.println("Processes " + " Burst time " +
+
+                      " Waiting time " + " Turn around time");
+
+
+
+        // Calculate total waiting time and total turn
+
+        // around time
+
+        for (int i=0; i<n; i++)
+
+        {
+
+            total_wt = total_wt + wt[i];
+
+            total_tat = total_tat + tat[i];
+
+            System.out.println(" " + (i+1) + "\t\t" + bt[i] +"\t " +
+
+                              wt[i] +"\t\t " + tat[i]);
+
+        }
+
+
+
+        System.out.println("Average waiting time = " +
+
+                          (float)total_wt / (float)n);
+
+        System.out.println("Average turn around time = " +
+
+                           (float)total_tat / (float)n);
+
+    }
+
+
+
+    // Driver Method
+
+    public static void main(String[] args)
+
+    {
+
+        // process id's
+
+        int processes[] = { 1, 2, 3};
+
+        int n = processes.length;
+
+
+
+        // Burst time of all processes
+
+        int burst_time[] = {10, 5, 8};
+
+
+
+        // Time quantum
+
+        int quantum = 2;
+
+        findavgTime(processes, n, burst_time, quantum);
+
+    }
+}