Goal:
Improve the Vehicle class by adding a constructor that automatically initializes the passengers, fuelcap, and mpg fields.

Builder Implementation:
A constructor has been added to the Vehicle class to initialize the mentioned fields when an object is created.
The constructor has three parameters: p for passengers, f for fuelcap, and m for mpg.

Constructor Definition:
The Vehicle(int p, int f, int m) constructor initializes the fields:

Vehicle(int p, int f, int m) {
    passengers = p;
    fuelcap = f;
    mpg = m;
}

Class Methods:

range(): Calculates and returns the vehicle's range (miles it can travel on a full tank).
fuelneeded(int miles): Calculates and returns the amount of fuel needed to cover a given distance.

Adjust the use of the classes they use, removing the initialization of attributes in the main method and passing arguments to the constructor of the Vehicle class.

Ex:
Vehicle minivan = new Vehicle(7,16,21);
Vehicle sportscar = new Vehicle(2,14,12);