SystemsProgrammingAndOperatingSystem/Codes/Group B/Assignment - 5/Priority (Non-Preemptive).cpp

#include<iostream>
#include<limits.h> // for INT_MAX
using namespace std;

struct sjf {
    int burst, arrival, id, completion, waiting, turnaround, response, priority;
    bool active;
};

sjf meh[30];

class lesgo {
public:
    int n;

    void priorityIn() {
        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;
            meh[i].id = i;
            meh[i].active = false;
        }
        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 priorityProcess() {
        int k = 0; // Current time
        int completed = 0; // Number of completed processes

        while (completed < n) {
            int highestPriority = INT_MAX;
            int selectedProcess = -1;

            // Find the process with the highest priority (smallest priority number) that has arrived and is not completed
            for (int i = 1; i <= n; i++) {
                if (meh[i].arrival <= k && !meh[i].active && meh[i].priority < highestPriority) {
                    highestPriority = meh[i].priority;
                    selectedProcess = i;
                }
            }

            if (selectedProcess != -1) {
                // Mark the process as active
                meh[selectedProcess].active = true;

                // If the process is starting now, calculate response time
                if (meh[selectedProcess].response == 0) {
                    meh[selectedProcess].response = k - meh[selectedProcess].arrival;
                }

                // Execute the process
                k += meh[selectedProcess].burst;
                meh[selectedProcess].completion = k;
                meh[selectedProcess].turnaround = meh[selectedProcess].completion - meh[selectedProcess].arrival;
                meh[selectedProcess].waiting = meh[selectedProcess].turnaround - meh[selectedProcess].burst;

                completed++;
            } else {
                // If no process is ready to run, just increment time
                k++;
            }
        }
    }

    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 << " | " << meh[j].completion
                 << "             | " << meh[j].waiting
                 << "             | " << meh[j].turnaround
                 << "             | " << meh[j].response << "\n";
        }

        cout << "\nAverage completion time: " << totalCompletion / n;
        cout << "\nAverage waiting time: " << totalWaiting / n;
        cout << "\nAverage turnaround time: " << totalTurnaround / n;
    }
};

int main() {
    lesgo obj;
    obj.priorityIn();
    obj.priorityProcess();
    obj.displayMetrics();
    return 0;
}