Happy numbers

happynumbers.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python
+
+def happynumbers_step(n):
+    s = 0
+    for c in str(n):
+        s += int(c)**2
+    return s
+
+def happynumbers(n):
+    founds = []
+    s = n
+    while True:
+        founds.append(s)
+        s = happynumbers_step(s)
+        if s == n:
+            return False
+        elif s in founds:
+            return False
+        elif s == 1:
+            return True
+
+if __name__ == '__main__':
+    from sys import argv
+    if len(argv) > 1:
+        n = int(argv[1])
+    else:
+        n = 4
+    print("%d is a %s number" % (n,"happy" if happynumbers(n) else "unhappy"))