Download the file bank.cpp, add it to a project, study the code and run it.
You must understand this original code completely before you modify it.
After you modify it, it should produce the very same output!
Here is the output:

Customer: Smith Balance: $100.00
After $400.00 Deposit
Customer: Smith Balance: $500.00

Thinking about this transaction ...
$1000.00 Check
This transaction is not OK

Thinking about this transaction ...
$50.00 Check
This transaction is OK

After the transaction
Customer: Smith Balance: $450.00
Undoing following transaction:
$50.00 Check

After undoing
Customer: Smith Balance: $500.00
Press any key to continue

Make the following changes:

    Create 2 structs:
          one for a bank account,
          one for a banking transaction
    Each struct will have 2 members.

    Rewrite the program so that it uses the 2 structs whenever possible.
(If you have missed lecture, look at the class web site to see what we did.)
Rewriting the program with structs will require replacing many variable and
parameters declarations as well as removing reference parameters (&) and
adding return types/return statements.  Here are some examples of code written
with and without structs.

     When you are done, there will be no reference parameters (&) remaining.

     All the init routines will have return types, as will any function that modifies an account.
The return statement will be used to send back the new or modified thing (account or transaction).