Fibonacci example (imperative)

fibonacci.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+
+import sys
+
+def F(n):
+    a = 0
+    b = 1
+    while n > 0:
+        c = a
+        a = a + b
+        b = c
+        n = n - 1
+    return a
+
+def main():
+    for arg in sys.argv[1:]:
+        print("F(" + arg + "): " + str(F(int(arg))))
+
+if __name__ == "__main__":
+    main()