fixed round robin code

Codes/Group B/Assignment - 5/Round Robin (Preemptive).cpp

@@ -1,116 +1,110 @@
-#include <iostream>
-#include <queue>
-#include <vector>
-#include <iomanip> // For formatting output
+#include<iostream>
+#include<queue>
 using namespace std;
 
-struct process {
-    int burst, arrival, id, completion, priority, waiting, turnaround, response, remainingBurst;
-    bool active;
+struct Process{
+    int id, burst, arrival, remaining, completion, waiting, turnaround, response;
 };
+Process processes[30];
 
-process meh[30];
-
-class RoundRobin {
+class RoundRobin{
 public:
-    int n;
-    int timeQuantum;
+    int n, timeQuantum;
 
-    void inputProcesses() {
-        cout << "\nEnter number of processes: ";
-        cin >> n;
-        for (int i = 1; i <= n; i++) {
-            cout << "\nEnter arrival time of P" << i << ": ";
-            cin >> meh[i].arrival;
-            cout << "\nEnter burst time of P" << i << ": ";
-            cin >> meh[i].burst;
-            cout << "\nEnter priority of P" << i << ": ";
-            cin >> meh[i].priority; // Priority is not used in RR, but kept here for completeness.
-            meh[i].id = i;
-            meh[i].remainingBurst = meh[i].burst;
-            meh[i].active = false;
-        }
-        cout << "\nEnter time quantum: ";
-        cin >> timeQuantum;
-        cout << "\n  | Arrival | Burst | Priority\n";
-        for (int j = 1; j <= n; j++) {
-            cout << "P" << j << " | " << meh[j].arrival << "       | " << meh[j].burst << " | " << meh[j].priority << "\n";
+    void input(){
+        cout<<"\nEnter number of processes: ";
+        cin>>n;
+        for(int i = 0; i < n; i++){
+            cout<<"\nEnter arrival time of P"<<i<<": ";
+            cin>>processes[i].arrival;
+            cout<<"Enter burst time of P"<<i<<": ";
+            cin>>processes[i].burst;
+            processes[i].id = i;
+            processes[i].remaining = processes[i].burst;
+            processes[i].response = -1;
         }
+        cout<<"\nEnter time quantum: ";
+        cin>>timeQuantum;
     }
 
-    void roundRobinProcess() {
-        int k = 0; // Current time
-        int completed = 0; // Number of completed processes
-        queue<int> readyQueue;
+    void process(){
+        int currentTime = 0;
+        queue<int> q;
+        bool inQueue[30] = {false};
+        int completedProcesses = 0;
 
-        vector<bool> isProcessed(n + 1, false); // Track whether a process has been added to the ready queue
-
-        while (completed < n) {
-            // Add processes that have arrived to the ready queue
-            for (int i = 1; i <= n; i++) {
-                if (meh[i].arrival <= k && !isProcessed[i]) {
-                    readyQueue.push(i);
-                    isProcessed[i] = true;
-                }
+        for(int i = 0; i < n; i++){
+            if(processes[i].arrival <= currentTime){
+                q.push(i);
+                inQueue[i] = true;
             }
+        }
 
-            if (readyQueue.empty()) {
-                // If no process is in the queue, increment time
-                k++;
+        while(completedProcesses < n){
+            if(q.empty()){
+                currentTime++;
+                for(int i = 0; i < n; i++){
+                    if(!inQueue[i] && processes[i].arrival <= currentTime){
+                        q.push(i);
+                        inQueue[i] = true;
+                    }
+                }
                 continue;
             }
 
-            int currentProcess = readyQueue.front();
-            readyQueue.pop();
+            int idx = q.front();
+            q.pop();
 
-            // Calculate response time for the process if it starts now
-            if (!meh[currentProcess].active) {
-                meh[currentProcess].response = k - meh[currentProcess].arrival;
-                meh[currentProcess].active = true;
+            if(processes[idx].response == -1){
+                processes[idx].response = currentTime - processes[idx].arrival;
             }
 
-            int timeSlice = min(timeQuantum, meh[currentProcess].remainingBurst);
+            if(processes[idx].remaining <= timeQuantum){
+                currentTime += processes[idx].remaining;
+                processes[idx].remaining = 0;
+                processes[idx].completion = currentTime;
+                processes[idx].turnaround = processes[idx].completion - processes[idx].arrival;
+                processes[idx].waiting = processes[idx].turnaround - processes[idx].burst;
+                completedProcesses++;
+            }else{
+                currentTime += timeQuantum;
+                processes[idx].remaining -= timeQuantum;
+            }
 
-            // Process the current process
-            meh[currentProcess].remainingBurst -= timeSlice;
-            k += timeSlice;
+            for(int i = 0; i < n; i++){
+                if(!inQueue[i] && processes[i].arrival <= currentTime && processes[i].remaining > 0){
+                    q.push(i);
+                    inQueue[i] = true;
+                }
+            }
 
-            if (meh[currentProcess].remainingBurst == 0) {
-                meh[currentProcess].completion = k;
-                meh[currentProcess].turnaround = meh[currentProcess].completion - meh[currentProcess].arrival;
-                meh[currentProcess].waiting = meh[currentProcess].turnaround - meh[currentProcess].burst;
-                completed++;
-            } else {
-                // If the process is not finished, re-add it to the queue
-                readyQueue.push(currentProcess);
+            if(processes[idx].remaining > 0){
+                q.push(idx);
             }
         }
     }
 
-    void displayMetrics() {
+    void displayMetrics(){
         double totalWaiting = 0, totalTurnaround = 0, totalCompletion = 0;
 
-        cout << "\n\n  | Completion time | Waiting time | Turnaround time | Response time\n";
-        for (int j = 1; j <= n; j++) {
-            totalWaiting += meh[j].waiting;
-            totalTurnaround += meh[j].turnaround;
-            totalCompletion += meh[j].completion;
-            cout << "P" << j << " | " << setw(15) << meh[j].completion
-                 << " | " << setw(12) << meh[j].waiting
-                 << " | " << setw(15) << meh[j].turnaround
-                 << " | " << setw(12) << meh[j].response << "\n";
+        cout<<"\n\n  | Completion time | Waiting time | Turnaround time | Response time\n";
+        for(int i = 0; i < n; i++){
+            totalWaiting += processes[i].waiting;
+            totalTurnaround += processes[i].turnaround;
+            totalCompletion += processes[i].completion;
+            cout<<"P"<< processes[i].id<<" | "<<processes[i].completion<<"             | "<< processes[i].waiting<<"             | "<<processes[i].turnaround<<"             | "<<processes[i].response<<"\n";
         }
 
-        cout << "\nAverage completion time: " << totalCompletion / n;
-        cout << "\nAverage waiting time: " << totalWaiting / n;
-        cout << "\nAverage turnaround time: " << totalTurnaround / n;
+        cout<<"\nAverage completion time: "<<totalCompletion/n;
+        cout<<"\nAverage waiting time: "<<totalWaiting/n;
+        cout<<"\nAverage turnaround time: "<<totalTurnaround/n;
     }
 };
 
-int main() {
-    RoundRobin obj;
-    obj.inputProcesses();
-    obj.roundRobinProcess();
-    obj.displayMetrics();
+int main(){
+    RoundRobin rr;
+    rr.input();
+    rr.process();
+    rr.displayMetrics();
     return 0;
-}
+}