text.rb

 # The standard C library provides an important, low level function that many other
 # programming languages and tools rely on called `atof`.


 # The goal of atof is simple: to convert a correctly formatted string to a double


 # precision floating point number (also know as 64bit float, double, etc).
 # For example:
 #  ie  atof("574.32") => 574.32, atof("23") => 23.0, etc


 #
 # Lets implement this primitive parsing function ourselves!


 #  Constraints:
 #    You may use string library functions that return strings however you like.
 #      For instance, you may use regexes, split, etc.
 #    You may only pass single character strings into library functions that return numbers


 #      For instance, you can only pass a single digit '9' into parseInt or parseFloat functions, but not '9.9', or '99'.  You need to combine the results and parse the remaining input!


 #    You may pass multi character strings to any utility function you write yourself.
 #      Feel free to still create helper functions to divide the problem into steps.


 #  Non Concerns:
 #    Assume all inputs are validly formatted.  Do not worry about handling invalid
 #      input strings.


 #
 #  We will implement the full atof in small discrete steps, each focusing on a
 # specific domain of valid inputs and tests to pass.  Please demonstrate passing
 # all tests before proceeding to further atof features.
 # For example, pass all the positive integer tests before continuing on to handle
 # negative integers, etc.
 #
 # Do not stress if you don't complete the whole problem!  We'll work as through as
 # much of the problem as we have time to solve.



def atof(string)
 return nil
end

 def verify_input(string, expected)
     actual = atof(string)
     if actual != expected
         warn "Expected #{expected} but got #{actual}"
         return
     end
     puts "passed"
 end




# start with integers
verify_input("5", 5.0)
verify_input("50", 50.0)
verify_input("847600", 847600.0)
verify_input("0", 0.0)
verify_input("2", 2.0)
verify_input("139", 139.0)

# # negatives
verify_input("-23", -23.0)
verify_input("-2005", -2005.0)
verify_input("-23194", -23194.0)

# # floats
verify_input("-0.020350", -0.02035)
verify_input("125.4", 125.4)
verify_input("78493.119002", 78493.119002)

# # scientific notation
verify_input("254.03E6", 254030000)
verify_input("-0.31E-150", -3.1e-151)