round-robin.cpp

#include <bits/stdc++.h>

using namespace std;

struct process
{
    string id;
    int burst, waiting, turnaround;
};

int main()
{
    int size;
    cin >> size;
    vector<process> x(size);
    queue<process> waiting_list;

    for (int i = 0; i < size; i++)
    {
        cin >> x[i].id >> x[i].burst;
        waiting_list.push(x[i]);
    }
    
    int time_now = 0, quantum = 4;
    double avg_waiting = 0, avg_turnaround = 0;
    vector<pair<string, int>> timeline;

    while (!waiting_list.empty())
    {
        process now = waiting_list.front();
        waiting_list.pop();
        int quantum_now = min(now.burst, quantum);
        if (waiting_list.size() == 0)
        {
            quantum_now = now.burst;
        }
        time_now += quantum_now;
        timeline.push_back({now.id, time_now});
        now.burst -= quantum_now;
        if (!now.burst)
        {
            for (auto &p: x)
            {
                if (p.id == now.id)
                {
                    p.turnaround = time_now;
                    p.waiting = time_now - p.burst;
                    avg_waiting += p.waiting;
                    avg_turnaround += p.turnaround;
                    break;
                }
            }
        }
        else waiting_list.push(now);
    }

    string gantt_chart = "|", border = "-";
    for (auto z: timeline)
    {
        gantt_chart += "  " + z.first + "  |";
        border += "-------";
    }
    cout << "Gantt Chart:\n" << border << "\n" 
         << gantt_chart << "\n"
         << border << "\n"
         << "0";

    int index = 0;
    for (int i = 1; gantt_chart[i]; i++)
    {
        if (gantt_chart[i] == '|')
        {
            cout << timeline[index].second;
            if (timeline[index++].second >= 10) 
            {
                i++;
            }
        }
        else cout << " ";
    }

    cout << "\n\n"
         << "Average waiting time = " << avg_waiting / size << "\n"
         << "Average turnaround time = " << avg_turnaround / size << "\n\n"
         << "Process   |   Waiting Time   |   Turnaround Time\n"
         << "------------------------------------------------\n";
    for (int i = 0; i < size; i++)
    {
        cout << x[i].id << "              "
             << x[i].waiting << "                   "
             << x[i].turnaround << "\n";
    }
}

/*//... Sample Input-Output:
___________________________________________________________________________________________________________________________________________________________________________________________________________________________
Input:
3
P1 24
P2 3
P3 3
___________________________________________________________________________________________________________________________________________________________________________________________________________________________
Output:
Gantt Chart:
---------------------------------------------------------
|  P1  |  P2  |  P3  |  P1  |  P1  |  P1  |  P1  |  P1  |
---------------------------------------------------------
0      4      7      10     14     18     22     26     30  

Average waiting time = 5.66667
Average turnaround time = 15.6667

Process   |   Waiting Time   |   Turnaround Time
------------------------------------------------
P1              6                   30
P2              4                   7
P3              7                   10

*///...