Aidan bank thingy

bank.py

def get_current_num():
  f = open("statement", "r")
  num = int(f.read())
  f.close()
  return num

def write_new_num(n):
  f = open("statement", "w")
  stmt_string = str(n)
  f.write(stmt_string)
  f.close()

current_balance = None

try:
  current_balance = get_current_num()
  print("you have " + str(current_balance))
except IOError:
  current_balance = 0
  print 'Oh dear. You don\'t have an account. Creating one now...'

input_difference = int(raw_input("Enter amount to change by:").rstrip())
current_balance += input_difference
write_new_num(current_balance)