In computer programming, rank with no further specifications is usually a synonym for (or refers to) "number of dimensions"; thus, a two-dimensional array has rank two, a three-dimensional array has rank three and so on. Strictly, no formal definition can be provided which applies to every programming language, since each of them has its own concepts, semantics and terminology; the term may not even be applicable or, to the contrary, applied with a very specific meaning in the context of a given language.
In the case of APL the notion applies to every operand; and dyads ("binary functions") have a left rank and a right rank.
The box below instead shows how rank of a type and rank of an array expression could be defined (in a semi-formal style) for C++ and illustrates a simple way to calculate them at compile time.
#include<type_traits>#include<cstddef>/* Rank of a type * ------------- * * Let the rank of a type T be the number of its dimensions if * it is an array; zero otherwise (which is the usual convention) */template<typenameT>structrank{staticconststd::size_tvalue=0;};template<typenameT,std::size_tN>structrank<T[N]>{staticconststd::size_tvalue=1+rank<T>::value;};template<typenameT>constexprautorank_v=rank<T>::value;/* Rank of an expression * * Let the rank of an expression be the rank of its type */template<typenameT>usingunqualified_t=std::remove_cv_t<std::remove_reference_t<T>>;template<typenameT>autorankof(T&&expr){returnrank_v<unqualified_t<T>>;}
Given the code above the rank of a type T can be calculated at compile time by
rank<T>::value
or the shorter form
rank_v<T>
Calculating the rank of an expression can be done using
Templates are a feature of the C++ programming language that allows functions and classes to operate with generic types. This allows a function or class to work on many different data types without being rewritten for each one.
Generic programming is a style of computer programming in which algorithms are written in terms of types to-be-specified-later that are then instantiated when needed for specific types provided as parameters. This approach, pioneered by ML in 1973, permits writing common functions or types that differ only in the set of types on which they operate when used, thus reducing duplication. Such software entities are known as generics in Python, Ada, C#, Delphi, Eiffel, F#, Java, Rust, Swift, TypeScript and Visual Basic .NET. They are known as parametric polymorphism in ML, Scala, Julia, and Haskell ; templates in C++ and D; and parameterized types in the influential 1994 book Design Patterns.
Template metaprogramming (TMP) is a metaprogramming technique in which templates are used by a compiler to generate temporary source code, which is merged by the compiler with the rest of the source code and then compiled. The output of these templates include compile-time constants, data structures, and complete functions. The use of templates can be thought of as compile-time polymorphism. The technique is used by a number of languages, the best-known being C++, but also Curl, D, and XL.
In mathematics and computer science, a higher-order function is a function that does at least one of the following:
In the C++ programming language, a copy constructor is a special constructor for creating a new object as a copy of an existing object. Copy constructors are the standard way of copying objects in C++, as opposed to cloning, and have C++-specific nuances.
Barton–Nackman trick is a term coined by the C++ standardization committee to refer to an idiom introduced by John Barton and Lee Nackman as Restricted Template Expansion.
The One Definition Rule (ODR) is an important rule of the C++ programming language that prescribes that objects and non-inline functions cannot have more than one definition in the entire program and template and types cannot have more than one definition by translation unit. It is defined in the ISO C++ Standard 2003, at section 3.2.
The computer programming languages C and Pascal have similar times of origin, influences, and purposes. Both were used to design their own compilers early in their lifetimes. The original Pascal definition appeared in 1969 and a first compiler in 1970. The first version of C appeared in 1972.
typedef is a reserved keyword in the C and C++ programming languages. It is used to create an alias name for another data type. As such, it is often used to simplify the syntax of declaring complex data structures consisting of struct and union types, but is just as common in providing specific descriptive type names for integer data types of varying lengths.
A class in C++ is a user-defined type or data structure declared with keyword class that has data and functions as its members whose access is governed by the three access specifiers private, protected or public. By default access to members of a C++ class is private. The private members are not accessible outside the class; they can be accessed only through methods of the class. The public members form an interface to the class and are accessible outside the class.
In the programming languages C and C++, the unary operator sizeof generates the size of an expression or a data type, measured in the number of char-sized storage units required for the type. Consequently, the construct sizeof (char) is guaranteed to be 1. The actual number of bits of type char is specified by the preprocessor macro CHAR_BIT, defined in the standard include file limits.h. On most modern systems this is eight bits. The result of sizeof has an unsigned integral type that is usually denoted by size_t.
The C and C++ programming languages are closely related but have many significant differences. C++ began as a fork of an early, pre-standardized C, and was designed to be mostly source-and-link compatible with C compilers of the time. Due to this, development tools for the two languages are often integrated into a single product, with the programmer able to specify C or C++ as their source language.
The curiously recurring template pattern (CRTP) is an idiom in C++ in which a class X derives from a class template instantiation using X itself as template argument. More generally it is known as F-bound polymorphism, and it is a form of F-bounded quantification.
C++11 is a version of the standard for the programming language C++. It was approved by International Organization for Standardization (ISO) on 12 August 2011, replacing C++03, superseded by C++14 on 18 August 2014 and later, by C++17. The name follows the tradition of naming language versions by the publication year of the specification, though it was formerly named C++0x because it was expected to be published before 2010.
Substitution failure is not an error (SFINAE) refers to a situation in C++ where an invalid substitution of template parameters is not in itself an error. David Vandevoorde first introduced the acronym SFINAE to describe related programming techniques.
Expression templates are a C++ template metaprogramming technique that builds structures representing a computation at compile time, where expressions are evaluated only as needed to produce efficient code for the entire computation. Expression templates thus allow programmers to bypass the normal order of evaluation of the C++ language and achieve optimizations such as loop fusion.
In computer programming, variadic templates are templates that take a variable number of arguments.
"typename" is a keyword in the C++ programming language used when writing templates. It is used for specifying that a dependent name in a template definition or declaration is a type. In the original C++ compilers before the first ISO standard was completed, the typename keyword was not part of the C++ language and Bjarne Stroustrup used the class keyword for template arguments instead. While typename is now the preferred keyword, older source code may still use the class keyword instead.
C++14 is a version of the ISO/IEC 14882 standard for the programming language C++. It is intended to be a small extension over C++11, featuring mainly bug fixes and small improvements. Its approval was announced on August 18, 2014. C++14 was released on December 15, 2014.
C++17 is a revision of the ISO/IEC 14882 standard for the C++ programming language.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
