FCFS_CPU_scheduling_algorithm.cpp

/* C++ program for implementation of FCFS scheduling algorithm */

/* Given n processes with their Burst times, we find the average waiting time 
and average turnaround time using FCFS CPU scheduling Algorithm */

#include <iostream>
using namespace std;

void findWaitingTime(int processes[], int n,
                     int bt[], int wt[])
{
    wt[0] = 0;
    for (int i = 1; i < n; i++)
    {
        wt[i] = bt[i - 1] + wt[i - 1];
    }
}

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 wt[n], tat[n], total_wt = 0, total_tat = 0;
    findWaitingTime(processes, n, bt, wt);
    findTurnAroundTime(processes, n, bt, wt, tat);

    cout << "Processes "
         << " Burst time "
         << " Waiting time "
         << " Turn around time\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;
}

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

    int burst_time[] = {9, 4, 7};

    findavgTime(processes, n, burst_time);
    return 0;
}