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
	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() 
{ 
	 
	int n ,i;
	cout<<"enter number of processes"<<endl;
	cin >> n;
	int processes[n],burst_time[n] ;

	for(i=0;i<n;i++)
	{
	    processes[i]=i+1;
	    cout<<"Enter burst time of processes"<<i+1<<endl;
	    cin>>burst_time[i];
	}

	findavgTime(processes, n, burst_time); 

	return 0; 
}