Question

C++

Create an application named CarDemo that declares at least two Car objects and demonstrates how they can be incremented using an overloaded ++ operator.

Create a Car class that contains the following properties:

• Model - The car model (as a string)
• Mpg The car's miles per gallon (as a double)

Include two overloaded constructors. One accepts parameters for the model and miles per gallon; the other accepts a model and sets the miles per gallon to 20.

Overload a ++ operator that increases the miles per gallon value by 1. The CarDemo application creates at least one Car using each constructor and displays the Car values both before and after incrementation.

Answer 1

Code:

#include <iostream>
using namespace std;
class Car
{
public:
    string model;
    double mpg;
    // This constructor takes model and mpg and assigns them as values to class variables
    Car(string model,double mpg)
    {
        this->model = model;
        this->mpg = mpg;
    }
    // This constructor takes model number and assigns it to class variable and the mpg is set to 20
    Car(string model)
    {
        this->model = model;
        this->mpg = 20;
    }
    // Overloading ++ operator
    Car operator ++ () {
        // Pre incrementing the mpg
        ++mpg;
        // Returning an new object
        return Car(model,mpg);
    }
};

// Main function
int main() {
    // Creating two objects of Car class
    Car tesla = Car("Tesla");
    Car mustang = Car("Mustang",27);
    // Printing the contents of the objects before pre increment
    cout<<"Before increment"<<endl;
    cout<<"Model name:"<<tesla.model<<endl;
    cout<<"Miles per gallon:"<<tesla.mpg<<endl;
    cout<<"Model name:"<<mustang.model<<endl;
    cout<<"Miles per gallon:"<<mustang.mpg<<endl;

    cout<<"\n\n";

    // Pre incrementing the miles per gallon
    ++tesla;
    ++mustang;
    // Printing the contents of the objects after pre increment
    cout<<"After increment"<<endl;
    cout<<"Model name:"<<tesla.model<<endl;
    cout<<"Miles per gallon:"<<tesla.mpg<<endl;
    cout<<"Model name:"<<mustang.model<<endl;
    cout<<"Miles per gallon:"<<mustang.mpg<<endl;
    return 0;
}

Sample Output: