C++ Program for Preemptive SJF (Shortest Job First)

 

#include <bits/stdc++.h>

using namespace std;

struct Process {

  int pid;

  int burst_time;

  int wait_time;

  int turnaround_time;

};

bool compare(Process a, Process b) {

  return a.burst_time < b.burst_time;

}

int main() {

  int n;

  cout << "Enter the number of processes: ";

  cin >> n;

  Process p[n];

  for (int i = 0; i < n; i++) {

    p[i].pid = i + 1;

    cout << "Enter the burst time of process " << i + 1 << ": ";

    cin >> p[i].burst_time;

  }

  sort(p, p + n, compare);

  p[0].wait_time = 0;

  for (int i = 1; i < n; i++) {

    p[i].wait_time = p[i - 1].wait_time + p[i - 1].burst_time;

  }

  for (int i = 0; i < n; i++) {

    p[i].turnaround_time = p[i].burst_time + p[i].wait_time;

  }

  cout << "Process ID\tBurst Time\tWait Time\tTurnaround Time\n";

  for (int i = 0; i < n; i++) {

    cout << p[i].pid << "\t\t" << p[i].burst_time << "\t\t" << p[i].wait_time << "\t\t" << p[i].turnaround_time << endl;

  }

  return 0;

}