Modern C++ Programming Cookbook

Using explicit constructors and conversion operators to avoid implicit conversion

Before C++11, a constructor with a single parameter was considered a converting constructor. With C++11, every constructor without the explicit specifier is considered a converting constructor. Such a constructor defines an implicit conversion from the type or types of its arguments to the type of the class. Classes can also define converting operators that convert the type of the class to another specified type. All these are useful in some cases, but can create problems in other cases. In this recipe, we will see how to use explicit constructors and conversion operators.