HOW CAN I INHERIT THE BASE CLASS CONSTRUCTOR because I'm getting errorAND WHAT OTHER ADJUSTMENTS CAN I MAKE TO IMPROVE MY CODE?

Question

Every bank offers a checking account. Derive the class checkingAccount from the class bankAccount
(designed in part (a)). This class inherits members to store the account number and the balance from
the base class. A customer with a checking account typically receives interest, maintains a minimum
balance, and pays service charges if the balance
falls below the minimum balance. Add member
variables to store this additional information. In addition to the operations inherited from the base
class, this class should provide the following operations: set interest rate, retrieve interest rate, set
minimum balance, retrieve minimum balance, set service charges, retrieve service charges, post
interest, verify if the balance is less than the minimum balance, write a check, withdraw (override the
method of the base class), and print account information. Add appropriate constructors.
https://code.sololearn.com/cS3Dp79RLNMw/?ref=app
https://code.sololearn.com/cS3Dp79RLNMw/?ref=app

Answer 1

The C++ course doesn't cover this very well, but you don't inherit constructors.
Well, C++11 introduced using in combination with base class constructors, which enables them to participate in overload resolution, which is practically the same. Writing

using bankAccount::bankAccount;

would make them visible in the derived class, but it won't fix your problem.
When derived class objects are initialized, first the base class has to be initialized. That means the derived class constructor has to call the base class constructor. If no such call is found, the base class is initialized by the default constructor. However, you did not provide a default constructor, only the parametrized one, so you have to call it explicitly:

checkingAccount (
int accountNumber,
double balance,
double i,
double t,
double u
) : bankAccount( accountNumber, balance )
{
// initialize derived attributes...
}

As you can see, the call is done via the member initializer list.

Answer 2

Supplement: I did my best to somewhat tidy your code. Maybe that's only me, but whitespaces are free while increasing the readability of your code, no need to be miserly with them.
That said, some things I want to note about the code itself:
1. Some of your methods, e.g. deposit(), were declared to return a double value, but actually didn't return anything, so I made them void for now.
2. You prefixed calls to base class methods with bankAccount::, which is something you can, but don't have to do, since you inherit them, so they belong to checkingAccount now anyway. I went one step further and made the attributes of bankAccount protected instead of private, this way you can use them directly in checkingAccount.
3. Note that for the account numbers, leading zeros are skipped, e.g. 0000 becomes 0.
If you want numbers such as 0000 as valid numbers, accountNumber should be a string instead of an int.

Answer 3

Supplement to supplement:
4. You forgot to actually deposit the money in your deposit() method, as you never changed the balance.
5. Your overriden withdraw() method is exactly the same as the one from bankAccount, that is not the purpose of overriding methods. I am not into banking, but perhaps you could check if depositing x violates the minimum balance instead of zero. Anyway, you should improve the method.
6. You could include some checks in your setters to make sure no invalid values are assigned to your attributes, e.g. a negative account number.

TL;DR: You are on a good way but should review certain aspects of your code and design.

With all of this out of the way, here's the refactored code:
https://code.sololearn.com/c1ugfG5Dvcpx/?ref=app