C++: A Dialog Programming with the C++ Standard Library

Calling operator=

Now that we've dissected the header into its atomic components, the actual implementation of the function should be trivial by comparison. But first there's a loose end to be tied up. That is, why was this function named string::operator = called in the first place? The line that caused the call was very simple: s = n;. There's no explicit mention of string or operator.

This is another of the ways in which C++ supports classes. Because you can use the = operator to assign one variable of a native type to another variable of the same type, C++ provides the same syntax for user defined variable types. Similar reasoning applies to operators like >, <, and so on, for classes where these operators make sense.

When the compiler sees ...