ACTIVITY 1 FR

#include <iostream>
#include <vector>
#include <limits>  // For std::numeric_limits
#include <iomanip> // For std::setw

using namespace std;

struct Process {
    int id;
    int arrival_time;
    int burst_time;
    int completion_time;
    int turnaround_time;
    int waiting_time;
    int response_time;
    int remaining_burst_time;
};

struct GanttChartEntry {
    int process_id;
    int start_time;
    int end_time;
};

void shortest_job_first(vector<Process>& processes, vector<GanttChartEntry>& gantt_chart) {
    int n = processes.size();
    int current_time = 0;
    int completed = 0;

    while (completed < n) {
        int min_burst_time = numeric_limits<int>::max();
        int idx = -1;

        for (int i = 0; i < n; ++i) {
            if (processes[i].arrival_time <= current_time &&
                processes[i].remaining_burst_time > 0 &&
                processes[i].remaining_burst_time < min_burst_time) {
                min_burst_time = processes[i].remaining_burst_time;
                idx = i;
            }
        }

        if (idx != -1) {
            // Set response time only if this is the first time the process is being executed
            if (processes[idx].remaining_burst_time == processes[idx].burst_time) {
                processes[idx].response_time = current_time - processes[idx].arrival_time;
            }

            // Record Gantt Chart Entry
            GanttChartEntry entry;
            entry.process_id = processes[idx].id;
            entry.start_time = current_time;

            current_time += processes[idx].remaining_burst_time;
            processes[idx].completion_time = current_time;
            processes[idx].turnaround_time = processes[idx].completion_time - processes[idx].arrival_time;
            processes[idx].waiting_time = processes[idx].turnaround_time - processes[idx].burst_time;
            processes[idx].remaining_burst_time = 0;
            ++completed;

            // End time for Gantt chart
            entry.end_time = current_time;
            gantt_chart.push_back(entry);
        } else {
            ++current_time;  // If no process is ready, just increment time
        }
    }
}

void print_gantt_chart(const vector<GanttChartEntry>& gantt_chart) {
    cout << "\nGantt Chart:\n";
    cout << "-------------------------------------------------\n";

    // Print the processes in the Gantt chart
    for (const auto& entry : gantt_chart) {
        cout << "|  P" << entry.process_id << "  ";
    }
    cout << "|\n";

    cout << "-------------------------------------------------\n";

    // Print the start times for each process
    for (const auto& entry : gantt_chart) {
        cout << entry.start_time << "\t";
    }
    // Print the last end time
    cout << gantt_chart.back().end_time << "\n";
}

void print_results(const vector<Process>& processes) {
    cout << "\nProcess ID\tArrival Time\tBurst Time\tCompletion Time\tTurnaround Time\tWaiting Time\tResponse Time" << endl;
    for (const auto& p : processes) {
        cout << "P" << p.id << "\t\t"
             << p.arrival_time << "\t\t"
             << p.burst_time << "\t\t"
             << p.completion_time << "\t\t"
             << p.turnaround_time << "\t\t"
             << p.waiting_time << "\t\t"
             << p.response_time << endl;
    }
}

int main() {
    vector<Process> processes(5);
    vector<GanttChartEntry> gantt_chart;

    cout << "Enter arrival and burst times for 5 processes:" << endl;
    for (int i = 0; i < 5; ++i) {
        processes[i].id = i + 1;
        cout << "Arrival time for Process " << processes[i].id << ": ";
        cin >> processes[i].arrival_time;
        cout << "Burst time for Process " << processes[i].id << ": ";
        cin >> processes[i].burst_time;
        processes[i].remaining_burst_time = processes[i].burst_time;
    }

    shortest_job_first(processes, gantt_chart);
    print_results(processes);
    print_gantt_chart(gantt_chart);

    return 0;
}