MPG Program

// MPG
/*		At the beginning of a car journey the driver ensures that the car's 
		fuel tank is full and records the odometer reading. After the journey he records 
		the new reading and how much fuel it took to refill the tank. Develop a 
		program which will calculate the fuel consumption.
*/

#include "stdafx.h"
#include <iostream>

using namespace std;

//methods
void input();
void calculations();
void output();

//global variables
double consumption = 0.0;
int distance_travelled;

int _tmain(int argc, _TCHAR* argv[])
{
	input();
	calculations();
	return 0;
}

void input()
{
		int first, second;
		cout << "What was your first reading : ";
		cin >> first;
		cout << "What was your second reading : ";
		cin >> second;
		distance_travelled = second - first;
}

void calculations()
{
	double refill, refill_litres;
	cout << "How many litres have you topped up : ";
	cin >> refill_litres;
	refill = refill_litres * 0.219969;
	consumption = distance_travelled/refill;
	output();
}

void output()
{
	cout << "Your MPG was : " << consumption << endl;
}