Implementing the Constructor

You might have thought of equally valid names. The account number should be a String because it is not expected to take part in arithmetic operations. Sometimes account numbers contain dashes or other non-digit characters. The balance is kept in terms of cents, so should be an int.

So far, the CheckingAccount class looks like this:

class CheckingAccount
{
  // instance variables
  String accountNumber;
  String accountHolder;
  int    balance;

   constructors

   methods

}

Next, consider the constructor. The constructor has the same name as the class, and looks like this:

  CheckingAccount( parameter-list )
  {
    initialize the data
  }

The constructor is used with the new operator to create a new checking account object. It then initializes the account number, the account holder's name, and starting balance. Actual parameters are supplied to the constructor when it is used, such as in the following:

  CheckingAccount billsAccount = 
          new CheckingAccount( "123", "Bob", 100 ) ;

This statement creates a new CheckingAccount object by calling the constructor. The constructor will initialize the object's accountNumber to "123", its accountHolder to "Bob", and its balance to 100.

CheckingAccount(   ,   ,  )
{
  initialize the data
}