Hands-On Design Patterns with C++

Method chaining

Method chaining is a borrowed C++ technique; it originates in Smalltalk. Its main purpose is to eliminate unnecessary local variables. You have used method chaining already, although you may not have realized it. Consider this code that you have probably written many times:

int i, j;std::cout << i << j;

The last line invoked the inserter operator << twice. The first time it is invoked on the object on the left-hand side of the operator, std::cout. What object is the second call on? In general, the operator syntax is just a way to call a function named operator<<(). Usually, this particular operator is a non-member function, but the std::ostream class has several member function overloads as well, and one of them is for int ...