Question

*** USING C++ ***

Create a file containing the following: car numbers, miles driven, and gallons of gas used in each car (do not include the readings): Car Number 25 Gallons Used 65 138 36 Miles Driven 1500 3540 1889 2466 2265 68 87 Write a program that reads the data in the file and displays the car number, miles driven, gallons used and the miles per gallon for each car. The output should also contain the total miles drive, total gallons used, and average miles per gallon for all the cars. These totals should be displayed at the end of the output report.

Answer 1

// C++ program to read the input file and calculate the MPG for each car and calculate and display the total miles driven, total gallons used and average MPG for all cars
#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;

int main()
{
ifstream fin("car_readings.txt"); // open the input file, provide full path to file
int carNumber, milesDriven, gallonsUsed;
double mpg, total_miles_driven = 0, total_gallons_used = 0, avg_mpg = 0;
int numCars=0;
// if file can be opened
if(fin.is_open())
{
cout<<left<<setw(15)<<"Car Number"<<left<<setw(15)<<"Miles Driven"<<left<<setw(15)<<"Gallons Used"<<left<<setw(10)<<"MPG"<<endl;
cout<<fixed<<setprecision(2);
// read till the end of file
while(!fin.eof())
{
fin>>carNumber>>milesDriven>>gallonsUsed;
// calculate mpg
if(gallonsUsed > 0)
mpg = ((double)milesDriven)/gallonsUsed;
else
mpg = 0;
// add mpg to avg_mpg, milesdriven to total_miles_driven, gallonsUsed to total_gallons_used
avg_mpg += mpg;
total_miles_driven += milesDriven;
total_gallons_used += gallonsUsed;
numCars++; // increment number of cars
cout<<left<<setw(15)<<carNumber<<left<<setw(15)<<milesDriven<<left<<setw(15)<<gallonsUsed<<left<<setw(10)<<mpg<<endl;
}

fin.close(); // close the input file
// calculate average mpg
avg_mpg = avg_mpg/numCars;
// display summary data
cout<<endl<<"Total miles driven : "<<total_miles_driven<<endl;
cout<<"Total gallons used: "<<total_gallons_used<<endl;
cout<<"Average miles per gallon for all cars: "<<avg_mpg<<endl;
}else
cout<<"Unable to open file : car_readings.txt"<<endl;

return 0;
}
//end of program

Output:

Input file:

Values in a line must be separated by a single space or tab

Format of a line in the file : <car number><space><miles driven><space><gallons used>

25 1500 65 36 3540 138 | 44 1889 65 52 2466 115 68 2265 8

Output:

Car Number 25 Gallons Used 65 138 36 Miles Driven 1500 3540 1889 2466 2265 MPG 23.08 25.65 29.06 21.44 26.03 44 65 52 115 68 87 Total miles driven : 11660.00 Total gallons used: 470.00 Average miles per gallon for all cars: 25.05