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// C++ program for implementation of RR scheduling
#include<iostream>
using namespace std;

// Function to find the waiting time for all
// processes
void findWaitingTime(int processes[], int n,
int bt[], int wt[], int quantum)
{
// Make a copy of burst times bt[] to store remaining
// burst times.
int rem_bt[n];
for (int i = 0 ; i < n ; i++)
rem_bt[i] = bt[i];

int t = 0; // Current time

// Keep traversing processes in round robin manner
// until all of them are not done.
while (1)
{
bool done = true;

// Traverse all processes one by one repeatedly
for (int i = 0 ; i < n; i++)
{
// If burst time of a process is greater than 0
// then only need to process further
if (rem_bt[i] > 0)
{
done = false; // There is a pending process

if (rem_bt[i] > quantum)
{
// Increase the value of t i.e. shows
// how much time a process has been processed
t += quantum;

// Decrease the burst_time of current process
// by quantum
rem_bt[i] -= quantum;
}

// If burst time is smaller than or equal to
// quantum. Last cycle for this process
else
{
// Increase the value of t i.e. shows
// how much time a process has been processed
t = t + rem_bt[i];

// Waiting time is current time minus time
// used by this process
wt[i] = t - bt[i];

// As the process gets fully executed
// make its remaining burst time = 0
rem_bt[i] = 0;
}
}
}

// If all processes are done
if (done == true)
break;
}
}

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

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

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

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

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

// Calculate total waiting time and total turn
// around time
for (int i=0; i<n; i++)
{
total_wt = total_wt + wt[i];
total_tat = total_tat + tat[i];
cout << " " << i+1 << "tt" << bt[i] <<"t "
<< wt[i] <<"tt " << tat[i] <<endl;
}

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

// Driver code
int main()
{
// process id's
int processes[] = { 1, 2, 3};
int n = sizeof processes / sizeof processes[0];

// Burst time of all processes
int burst_time[] = {10, 5, 8};

// Time quantum
int quantum = 2;
findavgTime(processes, n, burst_time, quantum);
return 0;
}