OS/SJN.cpp at master · aniketshahi/OS · GitHub

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#include <iostream>
using namespace std;

void sjf(int p, int process[], int arrival[], int burst[], int wait[], int turnaround[], int completion[])
{
    int i, j, pos, temp;
    int total = 0, t = 0, min;
    float avg_wt, avg_tat;

    // Initialize wait and turnaround times
    for (i = 0; i < p; i++)
    {
        wait[i] = 0;
        turnaround[i] = 0;
        completion[i] = -1;
    }

    // Sort processes based on arrival time
    for (i = 0; i < p - 1; i++)
    {
        pos = i;
        for (j = i + 1; j < p; j++)
        {
            if (arrival[j] < arrival[pos])
            {
                pos = j;
            }
        }
        temp = process[i];
        process[i] = process[pos];
        process[pos] = temp;
        temp = arrival[i];
        arrival[i] = arrival[pos];
        arrival[pos] = temp;
        temp = burst[i];
        burst[i] = burst[pos];
        burst[pos] = temp;
    }

    // Calculate completion times, waiting times, and turnaround times
    for (i = 0; i < p; i++)
    {
        min = 100000;
        pos = -1;
        for (j = 0; j < p; j++)
        {
            if (arrival[j] <= t && completion[j] == -1)
            {
                if (burst[j] < min)
                {
                    min = burst[j];
                    pos = j;
                }
            }
        }
        if (pos != -1)
        {
            completion[pos] = t + burst[pos];
            wait[pos] = completion[pos] - arrival[pos] - burst[pos];
            if (wait[pos] < 0)
            {
                wait[pos] = 0;
            }
            turnaround[pos] = completion[pos] - arrival[pos];
            total += turnaround[pos];
            t = completion[pos];
        }
        else
        {
            t++;
        }
    }

    // Calculate average waiting time and turnaround time
    avg_wt = (float)total / p;
    avg_tat = (float)total / p;

    // Display output
    cout << "Process\tArrival Time\tBurst Time\tWaiting Time\tCompletion Time\tTurnaround Time\n";
    for (i = 0; i < p; i++)
    {
        cout << process[i] << "\t" << arrival[i] << "\t\t" << burst[i] << "\t\t" << wait[i] << "\t\t" << completion[i] << "\t\t" << turnaround[i] << "\n";
    }
    cout << "\nAverage Waiting Time: " << avg_wt << "\n";
    cout << "Average Turnaround Time: " << avg_tat << "\n";
    cout << "\nThroughput: " << (float)p / t << "\n";
    cout << "CPU Utilization: " << (float)total / t << "\n";
}

int main()
{
    int n;
    cout << "Enter the number of processes: ";
    cin >> n;
    int p = n;
    int process[n], arrival[n], burst[n];
    for (int i = 0; i < n; i++)
    {
        cout << "Enter the arrival time and burst time for process " << i + 1 << ": ";
        cin >> arrival[i] >> burst[i];
        process[i] = i + 1;
    }

    int wait[p], turnaround[p], completion[p];
    sjf(p, process, arrival, burst, wait, turnaround, completion);
    // rest of the SJF code here
    return 0;
}