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std::numeric_limits — cppreference.com

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Déclaré dans l'en-tête `<limits>`
`template< class T > class numeric_limits;`

Le modèle de classe numeric_limits fournit un moyen standard pour rechercher des propriétés différentes types fondamentaux (par exemple, la plus grande valeur possible pour le type int est std::numeric_limits<int>::max()) .

Original:

The numeric_limits class template provides a standardized way to query various properties of fundamental types (e.g. the largest possible value for type int is std::numeric_limits<int>::max()).

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Cette information est fournie par l'intermédiaire des spécialisations du modèle numeric_limits. La bibliothèque standard permet spécialisations disponibles pour tous les types fondamentaux:

Original:

This information is provided via specializations of the numeric_limits template. The standard library makes available specializations for all fundamental types:

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Déclaré dans l'en-tête `<limits>`
template<> class numeric_limits<bool>; template<> class numeric_limits<char>; template<> class numeric_limits<signed char>; template<> class numeric_limits<unsigned char>; template<> class numeric_limits<wchar_t>; template<> class numeric_limits<char16_t>; // C++11 feature template<> class numeric_limits<char32_t>; // C++11 feature template<> class numeric_limits<short>; template<> class numeric_limits<unsigned short>; template<> class numeric_limits<int>; template<> class numeric_limits<unsigned int>; template<> class numeric_limits<long>; template<> class numeric_limits<unsigned long>; template<> class numeric_limits<long long>; template<> class numeric_limits<unsigned long long>; template<> class numeric_limits<float>; template<> class numeric_limits<double>; template<> class numeric_limits<long double>;

En outre, une spécialisation existe pour chaque version de cv-qualifié de chaque type fondamental, identique à la spécialisation sans réserve, par exemple, std::numeric_limits<const int>, std::numeric_limits<volatile int> et std::numeric_limits<const volatile int> sont fournis et sont équivalentes à std::numeric_limits<int> .

Original:

Additionally, a specialization exists for every cv-qualified version of each fundamental type, identical to the unqualified specialization, e.g. std::numeric_limits<const int>, std::numeric_limits<volatile int>, and std::numeric_limits<const volatile int> are provided and are equivalent to std::numeric_limits<int>.

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Les types de bibliothèques standards qui sont des alias des types fondamentaux (tels que std::size_t ou std::streamsize peut également être consulté avec les caractères de std::numeric_limits .

Original:

The standard library types that are aliases of fundamental types (such as std::size_t or std::streamsize may also be examined with the std::numeric_limits type traits.

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implémentations peuvent fournir des spécialisations de std::numeric_limits de mise en œuvre spécifiques aux types: par ex. GCC fournit. std::numeric_limits<__int128> bibliothèques peuvent ajouter des spécialisations pour la bibliothèque fournis par types, par exemple OpenEXR dispose std::numeric_limits<half> pour un 16-bit virgule flottante de type .

Original:

Implementations may provide specializations of std::numeric_limits for implementation-specific types: e.g. GCC provides std::numeric_limits<__int128>. Libraries may add specializations for library-provided types, e.g. OpenEXR provides std::numeric_limits<half> for a 16-bit floating-point type.

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Constantes membres


is_specialized [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie les types pour lesquels std::numeric_limits est spécialisée Original: identifies types for which std::numeric_limits is specialized The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

is_signed [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie les types signés Original: identifies signed types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

is_integer [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie les types entiers Original: identifies integer types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

is_exact [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie les types exacts Original: identifies exact types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

has_infinity [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie types à virgule flottante qui peuvent représenter la valeur spéciale "infini positif" Original: identifies floating-point types that can represent the special value "positive infinity" The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

has_quiet_NaN [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie types à virgule flottante qui peuvent représenter la valeur spéciale "calme pas-a-number» (NaN) Original: identifies floating-point types that can represent the special value "quiet not-a-number" (NaN) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

has_signaling_NaN [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie types à virgule flottante qui peuvent représenter la valeur spéciale "signalisation non-a-number» (NaN) Original: identifies floating-point types that can represent the special value "signaling not-a-number" (NaN) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

has_denorm [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie le style utilisé par la dénormalisation du type à virgule flottante Original: identifies the denormalization style used by the floating-point type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

has_denorm_loss [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie les types à virgule flottante qui détectent une perte de précision que la perte de dénormalisation plutôt que des résultats inexacts Original: identifies the floating-point types that detect loss of precision as denormalization loss rather than inexact result The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

round_style [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie le type d'arrondi utilisé par le type Original: identifies the rounding style used by the type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

is_iec559 [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie les IEC 559/IEEE 754 types à virgule flottante Original: identifies the IEC 559/IEEE 754 floating-point types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

is_bounded [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie des types qui représentent un ensemble fini de valeurs Original: identifies types that represent a finite set of values The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

is_modulo [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie les types qui gèrent les débordements avec l'arithmétique modulo Original: identifies types that handle overflows with modulo arithmetic The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

digits [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	nombre de chiffres `radix` qui peuvent être représentées sans changement Original: number of `radix` digits that can be represented without change The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

digits10 [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	nombre de chiffres décimaux qui peuvent être représentées sans changement Original: number of decimal digits that can be represented without change The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

max_digits10 [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ] (C++11)	nombre de chiffres décimaux nécessaires pour différencier les valeurs de ce type Original: number of decimal digits necessary to differentiate all values of this type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

radix [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	la base ou la base utilisée par nombre entier de la représentation du type donné Original: the radix or integer base used by the representation of the given type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

min_exponent [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	un de plus que la plus petite puissance négative de la racine qui est valide normalisé valeur à virgule flottante Original: one more than the smallest negative power of the radix that is a valid normalized floating-point value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

min_exponent10 [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	la plus petite puissance négative de dix qui est valide normalisé valeur à virgule flottante Original: the smallest negative power of ten that is a valid normalized floating-point value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

max_exponent [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	un de plus que la plus grande puissance entière de la racine qui est valide finie valeur à virgule flottante Original: one more than the largest integer power of the radix that is a valid finite floating-point value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

max_exponent10 [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	la plus grande puissance entière de 10 qui est valide finie valeur à virgule flottante Original: the largest integer power of 10 that is a valid finite floating-point value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

traps [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie les types qui peuvent causer des opérations arithmétiques à piéger Original: identifies types which can cause arithmetic operations to trap The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

tinyness_before [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	identifie types à virgule flottante qui détectent tinyness avant arrondis Original: identifies floating-point types that detect tinyness before rounding The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) [edit]

Fonctions membres


min [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	renvoie la plus petite valeur finie du type donné Original: returns the smallest finite value of the given type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) [edit]

lowest [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ] (C++11)	renvoie la plus petite valeur finie du type donné Original: returns the lowest finite value of the given type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) [edit]

max [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	renvoie la plus grande valeur finie du type donné Original: returns the largest finite value of the given type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) [edit]

epsilon [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	renvoie la différence entre `1.0` et la prochaine valeur représentable de la donnée à virgule flottante de type Original: returns the difference between `1.0` and the next representable value of the given floating-point type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) [edit]

round_error [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	retourne l'erreur d'arrondi maximum de la donnée à virgule flottante de type Original: returns the maximum rounding error of the given floating-point type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) [edit]

infinity [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	renvoie la valeur infinie positive de la donnée à virgule flottante de type Original: returns the positive infinity value of the given floating-point type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) [edit]

quiet_NaN [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	renvoie une valeur NaN calme de la donnée à virgule flottante de type Original: returns a quiet NaN value of the given floating-point type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) [edit]

signaling_NaN [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	renvoie une valeur NaN de signalisation de la donnée à virgule flottante de type Original: returns a signaling NaN value of the given floating-point type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) [edit]

denorm_min [ statique Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. ]	retourne la plus petite valeur positive inférieure à la normale de la donnée à virgule flottante de type Original: returns the smallest positive subnormal value of the given floating-point type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) [edit]

Classes d'aide


	indique modes d'arrondi en virgule flottante Original: indicates floating-point rounding modes The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (enum) [edit]

	indique les modes de dénormalisation à virgule flottante Original: indicates floating-point denormalization modes The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (enum) [edit]

Relations avec les constantes C macro bibliothèque

Specialization	Members
Specialization	`min()`	`lowest()` (C++11)	`max()`	`epsilon()`	`digits`	`digits10`	`min_exponent`	`min_exponent10`	`max_exponent`	`max_exponent10`	`radix`
`_{numeric_limits<}bool_>`											`2`
`_{numeric_limits<}char_>`	CHAR_MIN	CHAR_MIN	CHAR_MAX								`2`
`_{numeric_limits<}signed char_>`	SCHAR_MIN	SCHAR_MIN	SCHAR_MAX								`2`
`_{numeric_limits<}unsigned char_>`	`0`	`0`	UCHAR_MAX								`2`
`_{numeric_limits<}wchar_t_>`	WCHAR_MIN	WCHAR_MIN	WCHAR_MAX								`2`
`_{numeric_limits<}char16_t_>`	`0`	`0`	UINT_LEAST16_MAX								`2`
`_{numeric_limits<}char32_t_>`	`0`	`0`	UINT_LEAST32_MAX								`2`
`_{numeric_limits<}short_>`	SHRT_MIN	SHRT_MIN	SHRT_MAX								`2`
`_{numeric_limits<}signed short_>`	SHRT_MIN	SHRT_MIN	SHRT_MAX								`2`
`_{numeric_limits<}unsigned short_>`	`0`	`0`	USHRT_MAX								`2`
`_{numeric_limits<}int_>`	INT_MIN	INT_MIN	INT_MAX								`2`
`_{numeric_limits<}signed int_>`	INT_MIN	INT_MIN	INT_MAX								`2`
`_{numeric_limits<}unsigned int_>`	`0`	`0`	UINT_MAX								`2`
`_{numeric_limits<}long_>`	LONG_MIN	LONG_MIN	LONG_MAX								`2`
`_{numeric_limits<}signed long_>`	LONG_MIN	LONG_MIN	LONG_MAX								`2`
`_{numeric_limits<}unsigned long_>`	`0`	`0`	ULONG_MAX								`2`
`_{numeric_limits<}long long_>`	LLONG_MIN	LLONG_MIN	LLONG_MAX								`2`
`_{numeric_limits<}signed long long_>`	LLONG_MIN	LLONG_MIN	LLONG_MAX								`2`
`_{numeric_limits<}unsigned long long_>`	`0`	`0`	ULLONG_MAX								`2`
`_{numeric_limits<}float_>`	FLT_MIN	`-FLT_MAX`	FLT_MAX	FLT_EPSILON	FLT_MANT_DIG	FLT_DIG	FLT_MIN_EXP	FLT_MIN_10_EXP	FLT_MAX_EXP	FLT_MAX_10_EXP	FLT_RADIX
`_{numeric_limits<}double_>`	DBL_MIN	`-DBL_MAX`	DBL_MAX	DBL_EPSILON	DBL_MANT_DIG	DBL_DIG	DBL_MIN_EXP	DBL_MIN_10_EXP	DBL_MAX_EXP	DBL_MAX_10_EXP	FLT_RADIX
`_{numeric_limits<}long double_>`	LDBL_MIN	`-LDBL_MAX`	LDBL_MAX	LDBL_EPSILON	LDBL_MANT_DIG	LDBL_DIG	LDBL_MIN_EXP	LDBL_MIN_10_EXP	LDBL_MAX_EXP	LDBL_MAX_10_EXP	FLT_RADIX

Exemple

#include <limits>
#include <iostream>

int main() 
{
    std::cout << "type\tlowest\thighest\n";
    std::cout << "int\t"
              << std::numeric_limits<int>::lowest() << '\t'
              << std::numeric_limits<int>::max() << '\n';
    std::cout << "float\t"
              << std::numeric_limits<float>::lowest() << '\t'
              << std::numeric_limits<float>::max() << '\n';
    std::cout << "double\t"
              << std::numeric_limits<double>::lowest() << '\t'
              << std::numeric_limits<double>::max() << '\n';
}

Résultat possible :

type    lowest         highest
int     -2147483648    2147483647
float   -3.40282e+38   3.40282e+38
double  -1.79769e+308  1.79769e+308