Conversion operators and constructors in C++

Lesson 6

Objective

ADT conversions
Comparing conversion operators and constructors

Understand when to use conversion operators and when to use constructors to perform conversion.
Here is a table that explains the differences between using a constructor for conversions and using a special conversion function.

Conversion Constructor	Conversion Operator
used to convert from built-in types to user-defined types	used to convert from user-defined to built-in types
always has only one "from-type" argument, while the "to-type" argument is implied	has no parameters
creates new objects of user-defined type	has no return type; creates built-in type object
available for both implicit and explicit conversions (it is used explicitly in either cast or functional form)	conversions occur implicitly in assignment expressions, in arguments to functions, and in values returned from functions

Please note: A conversion member function of the form A::operator B() and a constructor of the form B::B(const A&) both provide conversions from type A objects to type B objects. Having both in your class can result in ambiguity errors.
ADT Conversions Constructor - Quiz

Click the Quiz link below to take a short multiple-choice quiz on ADT conversions.
ADT Conversions Constructor - Quiz