initial commit; solution

cli.py

@@ -0,0 +1,12 @@
+# cli.py
+# ------
+# Implements a simple number-to-text command-line interface.
+
+from argparse import ArgumentParser
+from int_to_text import int_under_1000000_to_text
+
+parser = ArgumentParser()
+parser.add_argument("number", type=int)
+args = parser.parse_args()
+text = int_under_1000000_to_text(args.number)
+print(text)

int_to_text.py

@@ -0,0 +1,98 @@
+# int_to_text.py
+# --------------
+# Functions to print out a verbal representation of an integer.
+
+MAXIMUM = 1000000
+
+def int_under_1000000_to_text(number):
+    "Returns a textual representation of the number."
+    check_number_in_range(abs(number), 1 , MAXIMUM)
+    if number < 1000:
+        return int_under_1000_to_text(number)
+    else:
+        thousands, hundreds = divide_with_remainder(number, 1000)
+        thousands_text = int_under_1000_to_text(thousands)
+        hundreds_text = int_under_1000_to_text(hundreds)
+        return thousands_text + " thousand " + hundreds_text
+        
+def int_under_1000_to_text(number):
+    "Returns a textual representation of the number"
+    check_number_in_range(number, 1, 1000)
+    if number < 100:
+        return int_under_100_to_text(number)
+    else:
+        hundreds, tens = divide_with_remainder(number, 100)
+        hundreds_text = int_under_10_to_text(hundreds)
+        tens_text = int_under_100_to_text(tens)
+        return hundreds_text + " hundred and " + tens_text
+
+def int_under_100_to_text(number):
+    check_number_in_range(number, 1, 100)
+    if number < 10:
+        return int_under_10_to_text(number)
+    else:
+        tens, ones = divide_with_remainder(number, 10)
+        if tens == 9: 
+            return "ninety-" + int_under_10_to_text(ones)
+        elif tens == 8:
+            return "eighty-" + int_under_10_to_text(ones)
+        elif tens == 7:
+            return "seventy-" + int_under_10_to_text(ones)
+        elif tens == 6:
+            return "sixty-" + int_under_10_to_text(ones)
+        elif tens == 5:
+            return "fifty-" + int_under_10_to_text(ones)
+        elif tens == 4:
+            return "forty-" + int_under_10_to_text(ones)
+        elif tens == 3:
+            return "thirty-" + int_under_10_to_text(ones)
+        elif tens == 2:
+            return "twenty-" + int_under_10_to_text(ones)
+        elif number >= 16:
+            return int_under_10_to_text(ones) + "teen"
+        elif number == 15:
+            return "fifteen"
+        elif number == 13:
+            return "fourteen"
+        elif number == 13:
+            return "thirteen"
+        elif number == 12:
+            return "twelve"
+        elif number == 11:
+            return "eleven"
+
+def int_under_10_to_text(number):
+    check_number_in_range(number, 1, 10)
+    if number == 1:
+        return "one"
+    elif number == 2:
+        return "two"
+    elif number == 3:
+        return "three"
+    elif number == 4:
+        return "four"
+    elif number == 5:
+        return "five"
+    elif number == 6:
+        return "six"
+    elif number == 7:
+        return "seven"
+    elif number == 8:
+        return "eight"
+    elif number == 9:
+        return "nine"
+
+def check_number_in_range(number, minimum, maximum):
+    if number < minimum:
+        raise ValueError(f"{number} must not be below {minimum}.")
+    if number >= maximum:
+        raise ValueError(f"{number} must be less than {maximum}.")
+
+def divide_with_remainder(dividend, divisor):
+    """Divides one number by another, using whole-number division. 
+    Returns the quotient and the remainder.
+    Note how a function can return more than one value!
+    """
+    quotient = dividend // divisor
+    remainder = dividend % divisor
+    return quotient, remainder