FCFS- FIRST COME FIRST SERVE

First Come First Serve (FCFS)

• Jobs are executed on first come, first serve basis.
• It is a non-preemptive, pre-emptive scheduling algorithm.
• Easy to understand and implement.
• Its implementation is based on FIFO queue.
• Poor in performance as average wait time is high.

FIRST COME

 FIRST SERVE PROGRAM

import java.util.*;

class FCFS

{

public static void main(String args[])

{

Scanner in=new Scanner(System.in);

int p;

float t1=0,t2=0;

System.out.println("Enter number of processes");

p=in.nextInt();

int bt[]=new int[p];

System.out.println("Enter burst time");

for(int i=0;i<p;i++)

{

System.out.println("Burst time for P"+(i+1)+"=");

bt[i]=in.nextInt();

}

int wt[]=new int[p];

wt[0]=0;

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

{

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

t1+=wt[i];

}

int tat[]=new int[p];

for(int i=0;i<p;i++)

{

tat[i]=bt[i]+wt[i];

t2+=tat[i];

}

System.out.println("Process\tBurst time\tWaiting time\tTurn Around time");

for(int i=0;i<p;i++)

{

System.out.println("P"+(i+1)+"\t\t"+bt[i]+"\t\t"+wt[i]+"\t\t"+tat[i]);

}

float awt,atat;

System.out.println("Average Waiting time="+t1/p);

System.out.println("Average Turn Around time="+t2/p);

}

OUTPUT :

IF ANY ERRORS COMMENTS  :)