Question

A constructor that takes a single parameter of a type different from the class type is a ___________ constructor.

Short answer

Answer: A conversion constructor.

Step-by-step solution

Statement Completion

Based on the constructor description given, we can complete the statement as follows: A constructor that takes a single parameter of a type different from the class type is a **conversion** constructor.

Key concepts

C++ Constructors

In the world of C++, constructors play a crucial role in initializing objects. A constructor is a special kind of member function that initializes an object automatically when it's created. Constructors have the same name as the class and do not return any type, not even void. Their primary job is to allocate memory and initialize the data members of the class.

There are different types of constructors in C++:

• Default constructor: Takes no parameters and initializes objects with default values.
• Parameterized constructor: Takes parameters and uses them to initialize objects with specific values.
• Copy constructor: Takes a reference to an object of the same class and duplicates it.

Understanding constructors is fundamental for managing object lifecycles and ensuring the integrity of data within your C++ applications.

Class Type Conversion

C++ provides the ability to convert one data type into another. This feature is useful when you want to use objects of one type as if they were another type. Class type conversion in C++ can be either implicit or explicit. An implicit conversion is done by the compiler without any intervention from the programmer, whereas explicit conversions require the use of type casting.

A common use of class type conversion is converting basic data types to class types or vice versa. This is often facilitated by constructors and conversion functions. For instance, a class designed to represent complex numbers might have constructors that allow conversion from 'int' or 'float'. It's important to be mindful of conversions to prevent unintended behavior and ensure that your code is clean and understandable.

Single-parameter Constructor

A single-parameter constructor in C++ is one that takes exactly one parameter of any type. Its purpose is to enable implicit or explicit construction of objects. Notably, a single-parameter constructor that takes a parameter type different from its own class type is known as a conversion constructor. This special type of constructor allows objects of the class to be created and initialized with values of a different type.

For example, consider the following constructor declaration for a 'Time' class: Time(int h); This single-parameter constructor allows an object of the 'Time' class to be created from an integer representing hours. As the exercise indicates, such constructors facilitate conversions, though this can sometimes lead to issues with unexpected type conversions. To avoid these, the 'explicit' keyword can be used when declaring the constructor to require explicit type casting for conversion. With wise usage, single-parameter constructors can greatly enhance the versatility and usability of your C++ classes.