How long is a subnet mask?

The library in TR1 is based on a Boost library.

a. Regex b. Unordered Associative Containers c. Date d. all of the above

What is the output of the following statement? (In this question # signifies a blank space.)

cout << setw (6) << left << “hello” << setw(6) << right << 2.78; a) #hello2.78## b) #hello2.78### c) hello###2.78 d) hello####2.78