Add problem1 for exercise2
Add missing 'iomanip' include
Improve problem 1 comments
Add problem 2 from exercise 2
Rename problem 2 solution
Add second solution for problem 2
Separate namespace from includes in problem 1
Add problem 3 from exercise 2
Add problem 4 from exercise 2
Add problem 5 from exercise 2
Add problem 6 from exercise 2
Improve comments in problem 6
Add problem 7 from exercise 2