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Implicit type conversion, also known as coercion or type juggling, is an automatic type conversion by the compiler. Some programming languages allow compilers to provide coercion; others require it. In a mixed-type expression, data of one or more subtypes can be converted to a supertype as needed at runtime so that the program will run correctly.
The type can be a reference or an enumerator. All types of conversions that are well-defined and allowed by the compiler are performed using static_cast. [2] [failed verification] The static_cast<> operator can be used for operations such as: converting a pointer of a base class to a pointer of a non-virtual derived class (downcasting);
However, this allows other, unintended conversions as well. Because C++ bool is defined as an arithmetic type, it can be implicitly converted to integral or even floating-point types, which allows for mathematical operations that are not intended by the user. In C++11, the explicit keyword can now be applied to conversion operators. As with ...
[4] [5] Function types in C++ are usually hidden behind typedefs and typically have an explicit reference or pointer qualifier. To force the alternate interpretation, the typical technique is a different object creation or conversion syntax. In the type conversion example, there are two alternate syntaxes available for casts: the "C-style cast"
Conversion of the fractional part: Consider 0.375, the fractional part of 12.375. To convert it into a binary fraction, multiply the fraction by 2, take the integer part and repeat with the new fraction by 2 until a fraction of zero is found or until the precision limit is reached which is 23 fraction digits for IEEE 754 binary32 format.
explicit K:: operator R (); since C++11 — Note: for user-defined conversions, the return type implicitly and necessarily matches the operator name unless the type is inferred (e.g. operator auto (), operator decltype (auto)() etc.). dynamic cast conversion dynamic_cast<R>(a) No: No — const_cast conversion const_cast<R>(a) No: No ...
In C and C++, constructs such as pointer type conversion and union — C++ adds reference type conversion and reinterpret_cast to this list — are provided in order to permit many kinds of type punning, although some kinds are not actually supported by the standard language.
This is only allowable if the object is already an instance of the derived class, and so this conversion is inherently fallible. In many environments, type introspection can be used to obtain the type of an object instance at runtime, and then use this result to explicitly evaluate its type compatibility with another type.