CODEWITHSUNDEEP
javaclassvariables
andrepcg
andrepcg

Reputation: 1331

Java class variable number

I'm learning java and now I have this question.

I created a class named "Driver" and it will hold a driver's information (name and birthday).

To create a new driver I just need to do:

Driver d1 = new Driver("John", "01/01/1980");

Now imagine I have a program that will read x drivers information from a file. How can I create x drivers?

My problem is that i'm thinking I need x variables for x drivers but variables can only be hard-coded by me...

Upvotes: 0

Views: 110

Answers (4)

Eng.Fouad
Eng.Fouad

Reputation: 117627

Use simple array:

Driver[] drivers = {new Driver("John", "01/01/1980"),
                    new Driver("Smith", "02/02/1990")};

// or

Driver[] drivers = new Driver[2];
drivers[0] = new Driver("John", "01/01/1980");
drivers[1] = new Driver("Smith", "02/02/1990");

But array has fixed size once you create it. So, you can use ArrayList instead:

List<Driver> drivers = new ArrayList<Driver>();
drivers.add(new Driver("John", "01/01/1980"));
drivers.add(new Driver("Smith", "02/02/1990"));
// ...

Upvotes: 0

jtahlborn
jtahlborn

Reputation: 53694

you would create a List<Driver> (or some other collection, e.g. Map) in which to store all the Drivers.

Upvotes: 0

Etienne de Martel
Etienne de Martel

Reputation: 36984

What you need, essentially, is to read each driver one by one, and store them in a collection. There are multiple collection classes in Java, but ArrayList should do just fine in your case:

ArrayList<Driver> drivers = new ArrayList<Driver>();

Driver d1 = new Driver("John", "01/01/1980");
drivers.add(d1);

Upvotes: 2

Bozho
Bozho

Reputation: 597234

Or you can use an array or collection (List or Set):

List<Driver> drivers = new ArrayList<Driver>();
drivers.add(new Driver(..));
drivers.add(new Driver(..));

When reading from a file you usually use a loop. So on each iteration add the object to the list.

Upvotes: 2

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