Data commit

Task/Negative-base-numbers/Python/negative-base-numbers.py

@@ -0,0 +1,43 @@
+#!/bin/python
+from __future__ import print_function
+
+def EncodeNegBase(n, b): #Converts from decimal
+	if n == 0:
+		return "0"
+	out = []
+	while n != 0:
+		n, rem = divmod(n, b)
+		if rem < 0:
+			n += 1
+			rem -= b
+		out.append(rem)
+	return "".join(map(str, out[::-1]))
+
+def DecodeNegBase(nstr, b): #Converts to decimal
+	if nstr == "0":
+		return 0
+	
+	total = 0
+	for i, ch in enumerate(nstr[::-1]):
+		total += int(ch) * b**i
+	return total
+
+if __name__=="__main__":
+	
+	print ("Encode 10 as negabinary (expect 11110)")
+	result = EncodeNegBase(10, -2)
+	print (result)
+	if DecodeNegBase(result, -2) == 10: print ("Converted back to decimal")
+	else: print ("Error converting back to decimal")
+
+	print ("Encode 146 as negaternary (expect 21102)")
+	result = EncodeNegBase(146, -3)
+	print (result)
+	if DecodeNegBase(result, -3) == 146: print ("Converted back to decimal")
+	else: print ("Error converting back to decimal")
+
+	print ("Encode 15 as negadecimal (expect 195)")
+	result = EncodeNegBase(15, -10)
+	print (result)
+	if DecodeNegBase(result, -10) == 15: print ("Converted back to decimal")
+	else: print ("Error converting back to decimal")