a. There is no real advantage

b. boost::swap invokes swap overloads supplied with the passed type, if any

c. boost::swap is faster than std::swap

d. boost::swap does not throw exceptions

a. Yes. A visitor can only be applied to one or two variant arguments

b. Yes. A visitor can be applied to one or more arguments

c. No. The member operators take only one variant argument

d. None of the above

BOOST_STATIC_ASSERT(x == 0); // x is some variable

a. Yes, provided x is of an integral type

b. Yes, provided x is declared as a const static numeric variable

c. No, x is a variable, and its value cannot be known at compile time

d. Only expressions involving sizeof are valid in a BOOST_STATIC_ASSERT

a. X does not have a user-defined constructor or destructor

b. X can be copied by copying its memory layout bit-wise

c. X does not have a user-defined copy constructor or copy assignment operator

d. All of the above

a. The type is const char* and value is NULL

b. The type is double and value is 0.0

c. The type is std::string and value is the default constructed std::string

d. The type is boost::optional<double> and value is empty

a. Both throw the boost::empty_optional exception

b. get throws an exception, while get_ptr returns a null pointer

c. get asserts, while get_ptr returns a null pointer

d. Both get and get_ptr assert