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Ruby Ruby Objects and Classes Build a Bank Account Class Part 2: Transactions, credits, and debits

Adrian Yeow
Adrian Yeow
13,866 Points
Posted by Adrian Yeow
Adrian Yeow
13,866 Points

The arguments of a method

first, we define this method

def add_transaction(description, amount) @transaction.push(description: description, amount: amount) end

What I dont understand is this

Comparing this method

def credit(descrip, amount) add_transaction(description, amount) end

with this

def debit(description, amount) add_transaction(description, -amount) end

the first method will return an error to me when i sent in the wrong argument, what i dont understand is that i have always thought that any arguments will do as long as this sentence "add_transaction(description, amount)" is correct. can anyone guide me on this? any help will be much appreciated.

Maciej Czuchnowski
Maciej Czuchnowski
36,441 Points
Maciej Czuchnowski
Maciej Czuchnowski
36,441 Points

Please give an example of what you do and what error it displays.

3 Answers

Roberto Alicata
PLUS
Roberto Alicata
Courses Plus Student 39,959 Points
Roberto Alicata
Roberto Alicata
Courses Plus Student 39,959 Points 
def credit(descrip, amount) 
  add_transaction(description, amount)
end

bankaccount2.rb:9:in credit': undefined local variable or methoddescription' for # (NameError) 0x007fd73290c>

This error is right because when you call add_transaction method you pass the local variable description that is not defined (you used descrip in the parameters list of the credit method)

You must rewrite the code like this:

def credit(description, amount) 
  add_transaction(description, amount)
end
Andrew Stelmach
Andrew Stelmach
12,583 Points
Andrew Stelmach
Andrew Stelmach
12,583 Points

Don't know if this helps, but you have a typo: "-amount", instead of "amount" in your code there. If you copy/pasted this into your post it's probably messing up your code.

Andrew Stelmach
Andrew Stelmach
12,583 Points

Ah, maybe it's not a typo, come to think of it!

Adrian Yeow
Adrian Yeow
13,866 Points
Adrian Yeow
Adrian Yeow
13,866 Points

take note of this method def add_transaction(description, amount) @transaction.push(description: description, amount: amount) end

and how i got an error when i called add_transaction and pass in the wrong argument like this

def credit(descrip, amount) add_transaction(description, amount) end

this is the error displayed

bankaccount2.rb:9:in credit': undefined local variable or methoddescription' for #<BankAccount:0x007fd73290c c28> (NameError)

i know where the issue is, but i just need some explanation on the errors. Thanks!