UAHCode/CPE435/Lab7/round_Robin.cpp

#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <stdbool.h>
#include <unistd.h>

using namespace std;

int numProcesses;

struct process{
    int pid; //Process ID
    int burst_time; //CPU Burst Time
    int working_time; //Time this process executed, if  working_time==burst_time, process is complete
    int t_round; //turn around time, time needed for the process to complete
};



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


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];
}


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 time\n";
 
    // 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 << "\t\t" << bt[i] <<"\t "
            << wt[i] <<"\t\t " << tat[i] <<endl;
    }
 
    cout << "Average waiting time = "
        << (int)total_wt / (int)n;
    cout << "\nAverage turn around time = "
        << (int)total_tat / (int)n;
    cout << endl;
}

int main()
{
    struct process  pr[numProcesses];
    int quantumTime;

    cout << "Enter the number of processes: ";
    cin >> numProcesses;


    cout << "\nEnter Quantum Time (ms): ";
    cin >> quantumTime;

    for(int i=0; i<numProcesses; i++)
    {
        cout << "\nEnter PID for process " << i+1 << " (ms): ";
        cin >> pr[i].pid;

        cout << "\nEnter Burst Time for process " << i+1 << " (ms): ";
        cin >> pr[i].burst_time;
    }
   // int x = sizeof pr->pid / sizeof pr[0].pid;
    findavgTime(&pr->pid, numProcesses, &pr->burst_time, quantumTime);
}

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;
    }
}