robinround.cpp

#include<iostream>
using namespace std;


void findWaitingTime(int processes[], int n,
			int bt[], int wt[], int quantum)
{

	int rem_bt[n];
	for (int i = 0 ; i < n ; i++)
		rem_bt[i] = bt[i];

	int t = 0; // Current time


	while (1)
	{
		bool done = true;

		for (int i = 0 ; i < n; i++)
		{

			if (rem_bt[i] > 0)
			{
				done = false; // There is a pending process

				if (rem_bt[i] > quantum)
				{
		
					t += quantum;


					rem_bt[i] -= quantum;
				}

	
				else
				{

					t = t + rem_bt[i];

					
					wt[i] = t - bt[i];

				
					rem_bt[i] = 0;
				}
			}
		}

	
		if (done == true)
		break;
	}
}


void findTurnAroundTime(int processes[], int n,
						int bt[], int wt[], int tat[])
{

	for (int i = 0; i < n ; i++)
		tat[i] = bt[i] + wt[i];
}

void findavgTime(int processes[], int n, int bt[],
									int quantum)
{
	int wt[n], tat[n], total_wt = 0, total_tat = 0;

	
	findWaitingTime(processes, n, bt, wt, quantum);

	findTurnAroundTime(processes, n, bt, wt, tat);


	cout << "PN\t "<< " \tBT "
		<< " WT " << " \tTAT\n";

	for (int i=0; i<n; i++)
	{
		total_wt = total_wt + wt[i];
		total_tat = total_tat + tat[i];
		cout << " " << i+1 << "\t\t" << bt[i] <<"\t "
			<< wt[i] <<"\t\t " << tat[i] <<endl;
	}

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

int main()
{
	
	int processes[] = { 1, 2, 3};
	int n = sizeof processes / sizeof processes[0];

	
	int burst_time[] = {10, 5, 8};

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