Notes

#include <bits/stdc++.h>
using namespace std;

struct Process {
int pid; // Process ID
int bt; // Burst Time
int art; // Arrival Time
};

// Function to find the waiting time for all
// processes
void findWaitingTime(Process proc[], int n,
int wt[])
{
int rt[n];

// Copy the burst time into rt[]
for (int i = 0; i < n; i++)
rt[i] = proc[i].bt;

int complete = 0, t = 0, minm = INT_MAX;
int shortest = 0, finish_time;
bool check = false;

// Process until all processes gets
// completed
while (complete != n) {

// Find process with minimum
// remaining time among the
// processes that arrives till the
// current time`
for (int j = 0; j < n; j++) {
if ((proc[j].art <= t) &&
(rt[j] < minm) && rt[j] > 0) {
minm = rt[j];
shortest = j;
check = true;
}
}

if (check == false) {
t++;
continue;
}

// Reduce remaining time by one
rt[shortest]--;

// Update minimum
minm = rt[shortest];
if (minm == 0)
minm = INT_MAX;

// If a process gets completely
// executed
if (rt[shortest] == 0) {

// Increment complete
complete++;
check = false;

// Find finish time of current
// process
finish_time = t + 1;

// Calculate waiting time
wt[shortest] = finish_time -
proc[shortest].bt -
proc[shortest].art;

if (wt[shortest] < 0)
wt[shortest] = 0;
}
// Increment time
t++;
}
}

// Function to calculate turn around time
void findTurnAroundTime(Process proc[], int n,
int wt[], int tat[])
{
// calculating turnaround time by adding
// bt[i] + wt[i]
for (int i = 0; i < n; i++)
tat[i] = proc[i].bt + wt[i];
}

// Function to calculate average time
void findavgTime(Process proc[], int n)
{
int wt[n], tat[n], total_wt = 0,
total_tat = 0;

// Function to find waiting time of all
// processes
findWaitingTime(proc, n, wt);

// Function to find turn around time for
// all processes
findTurnAroundTime(proc, n, wt, tat);

// Display processes along with all
// details
cout << "Processes "
<< " Burst time "
<< " Waiting time "
<< " Turn around timen";

// Calculate total waiting time and
// total turnaround time
for (int i = 0; i < n; i++) {
total_wt = total_wt + wt[i];
total_tat = total_tat + tat[i];
cout << " " << proc[i].pid << "tt"
<< proc[i].bt << "tt " << wt[i]
<< "tt " << tat[i] << endl;
}

cout << "nAverage waiting time = "
<< (float)total_wt / (float)n;
cout << "nAverage turn around time = "
<< (float)total_tat / (float)n;
}

// Driver code
int main()
{
Process proc[] = { { 1, 6, 1 }, { 2, 8, 1 },
{ 3, 7, 2 }, { 4, 3, 3 } };
int n = sizeof(proc) / sizeof(proc[0]);

findavgTime(proc, n);
return 0;
}