FIRST COME FIRST SERVED (FCFS) Algorithm

As the name suggests in this algorithm process are schedule according to their arrival time, the process that comes first will be scheduled first and it will be in CPU until it completes it burst time.

C++ Program for FCFS Scheduling

//Implementation fo FIRST COME FIRST SERVE Using C++

#include <iostream>
#include <algorithm>
#include <stdio.h>

using namespace std;

struct Schedule
{
	string pro_id;
	int artime,bt,ct,ta,wt;
	/*
	artime = Arrival time, 
	bt = Burst time, 
	ct = Completion time, 
	ta = Turn around time, 
	wt = Waiting time
	*/

};

bool compare(Schedule p1,Schedule p2)
{
	return p1.artime<p2.artime;
	/* This process will always return TRUE if above condition comes*/
}

int main()
{

	Schedule process[100];
	//An array of Processes

	int cpunon=0;

	int n,i;
	//n = number of processes, i= iteration variable

	float percentage;

	printf("Enter the number of process::");
	scanf("%d",&n);

	printf("Enter the pro_id arrival time and brust time of n process\n");
	for(i=0;i<n;i++)
	{
		cin>>process[i].pro_id;
		scanf("%d",&process[i].artime);
		scanf("%d",&process[i].bt);
	}


	sort(process,process+n,compare);

	/*sort is a predefined funcion  defined in algorithm.h header file,
	it will sort the processes according to their arrival time*/

	cpunon=process[0].artime-0;

	// initial values

	process[0].ct=process[0].artime+process[0].bt;
	process[0].ta=process[0].ct-process[0].artime;
	process[0].wt=0;

	for(i=1;i<n;i++)
	{
		if(process[i].artime<=process[i-1].ct)
		{
			process[i].ct=process[i-1].ct+process[i].bt;
			process[i].ta=process[i].ct-process[i].artime;
			process[i].wt=process[i].ta-process[i].bt;
		}
		else
		{
			process[i].ct=process[i].bt+process[i].artime;
			process[i].ta=process[i].ct-process[i].artime;
			process[i].wt=process[i].ta-process[i].bt;
			cpunon+=process[i].artime-process[i-1].ct;
		}
	}
	
	percentage=(float)((process[n-1].ct-cpunon)/process[n-1].ct)*100;
	
	cout<<"OUTPUT"<<endl;
	for(i=0;i<n;i++)
	{
		//keep all statements in one line
		cout<<process[i].pro_id<<" "<<process[i].artime<<" "
		<<process[i].bt<<" "<<process[i].ct<<" "
		<<process[i].ta<<" "<<process[i].wt;
		
		cout<<endl;
	}

	return 0;
}

Output