Update Day_12.md

Author: darkprinx

Status/Day_12.md

@@ -1 +1,69 @@
+# Question 44
+### Level 1
+
+**Question:**
+***Write a program which can map() to make a list whose elements are square of numbers between 1 and 20 (both included).***
+
+---------------
+
+### Hints: Use map() to generate a list. Use lambda to define anonymous functions.
+---------------
+
+**Main Author's Solution: Python 2**
+```
+squaredNumbers = map(lambda x: x**2, range(1,21))
+print squaredNumbers
+```
+**My Solution: Python 3**
+```
+```
+----------------------------------------
+
+# Question 45
+### Level 1
+
+**Question:**
+***Define a class named American which has a static method called printNationality.***
+
+---------------------
+### Hints: Use @staticmethod decorator to define class static method.
+---------------------
+**Main Author's Solution: Python 2**
+```
+class American(object):
+ @staticmethod
+ def printNationality():
+ print "America"
+
+anAmerican = American()
+anAmerican.printNationality()
+American.printNationality()
+```
+**My Solution: Python 3**
+```
+```
+----------------------------------------
+
+7.2
+
+Question:
+Define a class named American and its subclass NewYorker. 
+
+Hints:
+
+Use class Subclass(ParentClass) to define a subclass.
+
+Solution:
+
+class American(object):
+ pass
+
+class NewYorker(American):
+ pass
+
+anAmerican = American()
+aNewYorker = NewYorker()
+print anAmerican
+print aNewYorker
+