Chapter 4, Problem 1P

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 traveled by the car and will then output 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.

Program Plan Intro

• Include required header files.
• Declare and initialize a constant value “lpg = 0.264179”.
• Define a function named “calc()” to calculate “milage”.
  • Declare a variable “gal”.
  • Compute “gal” and “milage”
  • Function to return “milage”.
• Define a “main()” function.
  • Declare the variables “lit” and “miles”.
  • Declare a variable “ch”.
  • “do… while” loop to get the user input repeatedly.
    • Get the “lit” and “miles” from the user.
    • Call “calc()” with an arguments “lit” and “miles” values and print the “milage”.
    • Get the user input to repeat the program or not.
  • The input is checked with the condition and repeat or exit the program.

Explanation of Solution

Program to compute number of miles per gallon the car delivered:

// Include required header files

#include <iostream>

using namespace std;

// Assign const value

float const lpg=0.264179;

// Function definition of calc()

float calc(float liters, float miles)

{

  // Declare gal

  float gal;

  // Compute gal

  gal = lpg * liters;

  // Compute milage

  float milage = miles/gal;

  // Return milage

  return(milage);

}

// Function definition of main()

int main()

{

  // Declare lit and miles

  float lit, miles;

  // Declare ch

  char ch;

  // do... while loop

  do{

    // Get the liters

cout<<"\nEnter the number of liters of gasoline: ";

    // Assign the user input to lit

    cin>>lit;

    // Get the miles

cout<<"\nEnter the number of miles Travelled: ";

    // Assign the user input to miles

    cin>>miles;

// Display the miles per gallon the car delivered

cout<<"\nNumber of miles per gallon the car delivered: ";

// Call the function cal() and return the result

    cout<< calc(lit, miles) << endl;

    // Get the user input

    cout<<"\nDo you want to repeat(y/n)??: ";

    // Assign the user input to ch

    cin>>ch;

  // While loop condition to check ch is equal to y

  }while(ch=='y' || ch=='Y');

  // Return 0

  return 0;

}

Sample Output

Enter the number of liters of gasoline:  5

Enter the number of miles Travelled:  30

Number of miles per gallon the car delivered: 22.7119

Do you want to repeat(y/n)??:  n