// C++ program to implement Shortest Job first 
#include<bits/stdc++.h> 
using namespace std; 

struct Process 
{ 
int pid; // Process ID 
int bt; // Burst Time 
}; 

// This function is used for sorting all 
// processes in increasing order of burst 
// time 
bool comparison(Process a, Process b) 
{ 
	return (a.bt < b.bt); 
} 

// Function to find the waiting time for all 
// processes 
void findWaitingTime(Process proc[], int n, int wt[]) 
{ 
	// waiting time for first process is 0 
	wt[0] = 0; 

	// calculating waiting time 
	for (int i = 1; i < n ; i++ ) 
		wt[i] = proc[i-1].bt + wt[i-1] ; 
} 

// Function to calculate turn around time 
void findTurnAroundTime(Process proc[], int n, 
						int wt[], int tat[]) 
{ 
	// calculating turnaround time by adding 
	// bt[i] + wt[i] 
	for (int i = 0; i < n ; i++) 
		tat[i] = proc[i].bt + wt[i]; 
} 

//Function to calculate average time 
void findavgTime(Process proc[], int n) 
{ 
	int wt[n], tat[n], total_wt = 0, total_tat = 0; 

	// Function to find waiting time of all processes 
	findWaitingTime(proc, n, wt); 

	// Function to find turn around time for all processes 
	findTurnAroundTime(proc, n, wt, tat); 

	// Display processes along with all details 
	cout << "\nProcesses "<< " 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 << " " << proc[i].pid << "\t\t"
			<< proc[i].bt << "\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 proc[] = {{1, 6}, {2, 8}, {3, 7}, {4, 3}}; 
	int n = sizeof proc / sizeof proc[0]; 

	// Sorting processes by burst time. 
	sort(proc, proc + n, comparison); 

	cout << "Order in which process gets executed\n"; 
	for (int i = 0 ; i < n; i++) 
		cout << proc[i].pid <<" "; 

	findavgTime(proc, n); 
	return 0; 
}