atoi.rb

# String#to_i converts a string to an integer:
#   "42".to_i # 42
#   "0".to_i # 0
#
# Implement a new function atoi(s) which takes a string and converts it to an integer without using to_i:
#   atoi("42") # 42
#   atoi("0")  # 0
# 
def atoi(s)
  -1 # not the right answer
end