C++ Primer Plus

The Overloaded << Operator

Most often, this book has used cout with the << operator, also called the insertion operator:

int clients = 22;cout << clients;

In C++, as in C, by default the << operator is used as the bitwise left-shift operator (see Appendix E, “Other Operators”). An expression such as x<<3 means to take the binary representation of x and shift all the bits three units to the left. Obviously, this doesn’t have a lot to do with output. But the ostream class redefines the << operator through overloading to output for the ostream class. In this guise, the << operator is called the insertion operator instead of the left-shift operator. (The left-shift operator earned this new role through its visual aspect, which suggests a flow of ...