Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for an old version of Boost. Click here to view this page for the latest version.
PrevUpHomeNext

set

Description

set is an Associative Sequence of heteregenous typed data elements. Type identity is used to impose an equivalence relation on keys. The element's type is its key. A set may contain at most one element for each key. Membership testing and element key lookup has constant runtime complexity (see Overloaded Functions).

Header
#include <boost/fusion/container/set.hpp>
#include <boost/fusion/include/set.hpp>
#include <boost/fusion/container/set/set_fwd.hpp>
#include <boost/fusion/include/set_fwd.hpp>
Synopsis
template <
    typename T0 = unspecified
  , typename T1 = unspecified
  , typename T2 = unspecified
    ...
  , typename TN = unspecified
>
struct set;

The variadic class interface accepts 0 to FUSION_MAX_SET_SIZE elements, where FUSION_MAX_SET_SIZE is a user definable predefined maximum that defaults to 10. Example:

set<int, char, double>

You may define the preprocessor constant FUSION_MAX_SET_SIZE before including any Fusion header to change the default. Example:

#define FUSION_MAX_SET_SIZE 20
Template parameters

Parameter

Description

Default

T0...TN

Element types

unspecified

Model of

Notation

S

A set type

s

An instance of set

e0...en

Heterogeneous values

fs

A Forward Sequence

Expression Semantics

Semantics of an expression is defined only where it differs from, or is not defined in Random Access Sequence and Associative Sequence.

Expression

Semantics

S()

Creates a set with default constructed elements.

S(e0, e1,... en)

Creates a set with elements e0...en.

S(fs)

Copy constructs a set from a Forward Sequence fs.

s = fs

Assigns to a set, s, from a Forward Sequence fs.

Example
typedef set<int, float> S;
S s(12, 5.5f);
std::cout << at_key<int>(s) << std::endl;
std::cout << at_key<float>(s) << std::endl;
std::cout << result_of::has_key<S, double>::value << std::endl;

PrevUpHomeNext