FCFS

 package fcfs;

import java.io.*;

import java.util.Scanner;

public class FCFS {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

System.out.println("enter no of process: ");

int n = sc.nextInt();

int pid[] = new int[n];   

int ar[] = new int[n];     

int bt[] = new int[n];    

int ct[] = new int[n];     

int ta[] = new int[n];     

int wt[] = new int[n];     

int temp;

float avgwt=0,avgta=0;

 

for(int i = 0; i < n; i++){

System.out.println("enter process " + (i+1) + " arrival time: ");

ar[i] = sc.nextInt();

System.out.println("enter process " + (i+1) + " brust time: ");

bt[i] = sc.nextInt();

pid[i] = i+1;

}

 

//sorting according to arrival times

for(int i = 0 ; i <n; i++){

for(int  j=0;  j < n-(i+1) ; j++){

if( ar[j] > ar[j+1] ){

temp = ar[j];

ar[j] = ar[j+1];

ar[j+1] = temp;

temp = bt[j];

bt[j] = bt[j+1];

bt[j+1] = temp;

temp = pid[j];

pid[j] = pid[j+1];

pid[j+1] = temp;

}

}

}

// finding completion times

for(int  i = 0 ; i < n; i++){

if( i == 0){

ct[i] = ar[i] + bt[i];

}else{

if( ar[i] > ct[i-1]){

ct[i] = ar[i] + bt[i];

}else {

ct[i] = ct[i-1] + bt[i];

}

}

ta[i] = ct[i] - ar[i] ;          

wt[i] = ta[i] - bt[i] ;          

avgwt += wt[i] ;               

avgta += ta[i] ;               

}

System.out.println("\npid  arrival  brust  complete turn waiting");

for(int  i = 0 ; i< n;  i++){

System.out.print("PId"+"  \t "+"Arrival Time"+"  \t "+"Burst Time"+"  \t "+"Completion Time"+"  \t "+"Turn Around Time"+"  \t "+"Waiting Time"+"  \t ");

System.out.println(pid[i] + "  \t " + ar[i] + "\t" + bt[i] + "\t" + ct[i] + "\t" + ta[i] + "\t"  + wt[i] ) ;

}

sc.close();

System.out.println("\naverage waiting time: "+ (avgwt/n));     

System.out.println("average turnaround time:"+(avgta/n));    

}

}