Fcfs.cpp

// C++ program for implementation of FCFS 
// 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[])
{

    // waiting time for first process is 0

    wt[0] = 0;
 

    // calculating waiting time

    for (int  i = 1; i < n ; i++ )

        wt[i] =  bt[i-1] + wt[i-1] ;
}
 
// 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 wt[n], tat[n], total_wt = 0, total_tat = 0;
 

    //Function to find waiting time of all processes

    findWaitingTime(processes, n, bt, wt);
 

    //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 = "

         << (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};
 

    findavgTime(processes, n,  burst_time);

    return 0;
}