added test_skill in bab 9

Author: poncoe

bab9_funcrecursive/test_skill/factorial.py

@@ -0,0 +1,20 @@
+# Find Factorial Value
+
+def factorial(x):
+    if (x == 0):
+        return 1
+    else:
+        return (x * factorial(x - 1))
+
+
+def Combination(n, r):
+    if r < 0:
+        return 'rasio cannot be negative'
+    else:
+        return factorial(n) // (factorial(r) * factorial(n - r))
+
+
+if __name__ == '__main__':
+    n = int(input("n= "))
+    r = int(input("r= "))
+    print(Combination(n, r))