Question

A liter is 0.264179 gallons. Write a program that will read in the number of liters of gasoline consumed by the user's car and the number of miles per gallon the car delivered. Your program should allow the user to repeat this calculation as often as the user wishes. Define a function to compute the number of miles per gallon. Your program should use a globally defined constant for the number of liters per gallon. After doing this... Modify your program so that it will take input data for two cars and output the number of miles per gallon delivered by each car. Your program will also announce which car has the best fuel efficiency (highest number of miles per gallon).

Need help modifying this program:

Add two void functions: one called userIntruction that tells the user what to do Another displayResult that displays the original information (number of liters and miles driven) and the result (miles per gallon). Unsure where to go from here, the above program will compile, but I'm a bit unsure how to proceed with the functions required.

Here is my source code:

#include <iostream>
using namespace std;

int main(void)
{
   const double GALLONS_PER_LITER = 0.264179;

   int liters = 0;
   double distance = 0.0;

   double mpg = 0.0;
   do
   {
       cout << "Please input how many liters of gasoline is in your vehicle: ";
       cin >> liters;

       cout << "Please input the distance in miles you traveled in your vehicle: ";
       cin >> distance;

       mpg = distance / (liters * GALLONS_PER_LITER);

       cout << "Your vehicle's MPG is: " << mpg << endl;

   } while (liters > -1);

   return 0;
}

Answer 1

#include <iostream>
#define GALLONS_PER_LITER 0.264179
using namespace std;
class fuel{

  
   double efficiency(int liters,double distance){
       return distance/(liters*GALLONS_PER_LITER);
   }
  
   void userinstruction(){
       cout << "You have to enter the distance travelled by your car in miles and how many litres of gasoline consumed";
       cout << "Enter -1 to quit";
   }
  
   void displayresult(double d1,double d2,int l1,int l2,double avg1,double avg2){
       cout << "Car1 travelled a distance of " << d1 <<endl;
       cout << "Car2 travelled a distance of " << d2 <<endl;
       cout << "Gasoline consumed by car1 " << l1 <<endl;
       cout << "Gasoline consumed by car2 " << l2 <<endl;
       if(avg1 > avg2)
           cout << "Car 1 has greater fuel efficiency";
       else
           cout << "Car 2 has greater fuel efficiency";
   }
int main(void)
{
int liters1 = 0 , liters2 = 0;
double distance1 = 0.0, distance2 = 0.0;

double mpg = 0.0;
do
{
        userinstruction();
cout << "Please input how many liters of gasoline is in your vehicle: ";
cin >> liters1;

cout << "Please input the distance in miles you traveled in your vehicle: ";
cin >> distance1;

cout << "Please input how many liters of gasoline is in your vehicle: ";
cin >> liters2;

cout << "Please input the distance in miles you traveled in your vehicle: ";
cin >> distance2;

double eff1 = efficiency(liters1,distance1);
double eff2 = efficiency(liters2,distance2);

       displayresult(distance1,distance2,liters1,liters2,eff1,eff2);

} while (liters1 > -1);

return 0;
}
};