Search results
Results from the WOW.Com Content Network
In the C and C++ languages, such non-portable constructs are generally grouped into three categories: Implementation-defined, unspecified, and undefined behavior. [3] The exact definition of unspecified behavior varies. In C++, it is defined as "behavior, for a well-formed program construct and correct data, that depends on the implementation."
The usage of a function template saves space in the source code file in addition to limiting changes to one function description and making the code easier to read. An instantiated function template usually produces the same object code, though, compared to writing separate functions for all the different data types used in a specific program.
It will merely serve as a function argument type to distinguish the expressions from other types (note the definition of a Vec constructor and operator+ below). template < typename E > class VecExpression { public : static constexpr bool is_leaf = false ; double operator []( size_t i ) const { // Delegation to the actual expression type.
The C++ template construct used above is widely cited [citation needed] as the genericity construct that popularized the notion among programmers and language designers and supports many generic programming idioms. The D language also offers fully generic-capable templates based on the C++ precedent but with a simplified syntax.
The curiously recurring template pattern (CRTP) is an idiom, originally in C++, in which a class X derives from a class template instantiation using X itself as a template argument. [1] More generally it is known as F-bound polymorphism , and it is a form of F -bounded quantification .
The following is a declaration of the concept "equality_comparable" from the <concepts> header of a C++20 standard library. This concept is satisfied by any type T such that for lvalues a and b of type T, the expressions a==b and a!=b as well as the reverse b==a and b!=a compile, and their results are convertible to a type that satisfies the concept "boolean-testable":
In any translation unit, a template, type, function, or object can have no more than one definition. Some of these can have any number of declarations. A definition provides an instance. In the entire program, an object or non-inline function cannot have more than one definition; if an object or function is used, it must have exactly one ...
The C++ Standard Library provides base classes unary_function and binary_function to simplify the definition of adaptable unary functions and adaptable binary functions. Adaptable function objects are important, because they can be used by function object adaptors: function objects that transform or manipulate other function objects.