if statement - Ruby program help (ATM program) -

i'm newb ruby user using ruby version 2.1.5p273 , below created atm simulator program takes user input of deposits , withdrawals, , displays balance after. struggling ifs, elses , loops. want put decision making statement in beginning, asks if user wants withdraw, deposit, check balance, or end session. want put decision making statement in end, asks if user wants continue (which go beginning, or end session). general idea of want below, overall program below idea code. know it's wrong it's want like, in making correct , working code appreciated.

print "would (w)ithdraw, (d)eposit, or (c)heck balance or (e)nd session? if "(w)ithdraw"  # i'd make "press w withdraw"               bank_account.withdraw elsif "(d)eposit"   #  i'd make "press d deposit"    bank_account.deposit elsif "(c)heck balance" #  i'd make "press c check balance"  bank_account.show_balance elseif "(e)nd session" #  i'd make "press e end session" end     #this program atm simulator, takes user input of deposits , withdrawals, ,     displays balance after.  class bankaccount    def initialize(name)    @transations = []    @balance = 0   end    def deposit    print "how deposit? "    amount = gets.chomp    @balance += amount.to_f    puts "$#{amount} deposited."   end    def withdraw    print "how withdraw?"    amount = gets.chomp    @balance -= amount.to_f    puts "#{amount} withdrawn"   end    def show_balance    puts "your balance #{@balance}"   end   end  bank_account = bankaccount.new("justin g") bank_account.class # => bankaccount  print "welcome jay's atm!\n" bank_account.deposit bank_account.show_balance bank_account.withdraw `enter code here`bank_account.show_balance puts "thank you" 

this rudimentary should started. please let me know if have additional questions on i'm doing in code. part should self-explanatory if you're familiar other object-oriented programming languages.

here's atm:

# atm.rb  require './bank_account.rb'  cmd = "" account = bankaccount.new("justin g")  puts "***welcome #{account.name}'s atm***\n\n"  while cmd != "e"   puts "would (w)ithdraw, (d)eposit or (c)heck balance?"   puts "you can (e)nd session."   cmd = gets.chomp    case cmd   when "w"     puts "how withdraw?"     amount = gets.chomp # expect float      # handle incorrect input somehow, either here or     # preferably in bankaccount#withdraw method     account.withdraw(amount)   when "d"     puts "how deposit?"     amount = gets.chomp # expect float      # handle incorrect input somehow, either here or     # preferably in bankaccount#deposit method     account.deposit(amount)   when "c"     puts "your balance $%.2f\n" % account.balance   else     # didn't understand command     puts "didn't understand command. try again." unless cmd == "e"   end end 

here's bank account code:

# bank_account.rb class bankaccount   attr_reader :name, :balance    def initialize(name)     @name = name     @transactions = []     @balance = 0.0   end    def withdraw(amount)     # todo: check amount valid, else error     @balance -= amount.to_f     # todo: check if sufficient funds available     puts "$%.2f withdrawn.\n" % amount   end    def deposit(amount)     # todo: check amount valid, else error     @balance += amount.to_f     puts "$%.2f deposited.\n" % amount   end end