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  2. Union type - Wikipedia

    en.wikipedia.org/wiki/Union_type

    In the example code below, data item VERS-NUM is defined as a 2-byte binary integer containing a version number. A second data item VERS-BYTES is defined as a two-character alphanumeric variable. Since the second item is redefined over the first item, the two items share the same address in memory, and therefore share the same underlying data ...

  3. Tagged union - Wikipedia

    en.wikipedia.org/wiki/Tagged_union

    If an element lies in both, there will be two effectively distinct copies of the value in A + B, one from A and one from B. In type theory, a tagged union is called a sum type. Sum types are the dual of product types. Notations vary, but usually the sum type A + B comes with two introduction forms inj 1: A → A + B and inj 2: B → A + B.

  4. printf - Wikipedia

    en.wikipedia.org/wiki/Printf

    An example of the printf function. printf is a C standard library function that formats text and writes it to standard output.. The name, printf is short for print formatted where print refers to output to a printer although the functions are not limited to printer output.

  5. Relational model - Wikipedia

    en.wikipedia.org/wiki/Relational_model

    The body is a set of tuples. A tuple is a collection of n values, where n is the relation's degree, and each value in the tuple corresponds to a unique attribute. [6] The number of tuples in this set is the relation's cardinality. [7]: 17–22 Relations are represented by relational variables or relvars, which can be reassigned.

  6. Tuple relational calculus - Wikipedia

    en.wikipedia.org/wiki/Tuple_relational_calculus

    (t.name = "Codd") — tuple t has a name attribute and its value is "Codd" Book(t) — tuple t is present in relation Book. The formal semantics of such atoms is defined given a database db over S and a tuple variable binding val : V → T D that maps tuple variables to tuples over the domain in S: v.a = w.b is true if and only if val(v)(a ...

  7. C++ Standard Library - Wikipedia

    en.wikipedia.org/wiki/C++_Standard_Library

    The C++ Standard Library provides several generic containers, functions to use and manipulate these containers, function objects, generic strings and streams (including interactive and file I/O), support for some language features, and functions for common tasks such as finding the square root of a number.

  8. Variadic template - Wikipedia

    en.wikipedia.org/wiki/Variadic_template

    The variadic template feature of C++ was designed by Douglas Gregor and Jaakko Järvi [1] [2] and was later standardized in C++11. Prior to C++11, templates (classes and functions) could only take a fixed number of arguments, which had to be specified when a template was first declared.

  9. C++11 - Wikipedia

    en.wikipedia.org/wiki/C++11

    In theory, this function could affect a global variable, call other non-runtime constant functions, etc. C++11 introduced the keyword constexpr, which allows the user to guarantee that a function or object constructor is a compile-time constant. [11] The above example can be rewritten as follows: