std::ptrdiff_t

 

C++

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Utilità libreria

Tipo di supporto (basic types, RTTI, type traits)

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Funzione oggetti

initializer_list (C++11)

bitset

hash (C++11)

Gli operatori relazionali Original: Relational operators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

rel_ops::operator!= rel_ops::operator> rel_ops::operator<= rel_ops::operator>=

Coppie e tuple Original: Pairs and tuples The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

pair

tuple (C++11)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

Swap, in avanti e spostare Original: Swap, forward and move The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

swap

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

declval (C++11)

 

Tipo di supporto

Tipi base Original: Basic types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Tipi fondamentali
Larghezza fissa interi tipi(C++11)
ptrdiff_t size_t max_align_t (C++11)	nullptr_t (C++11) offsetof NULL
Limiti numerici Original: Numeric limits The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
numeric_limits
C numerico limita interfaccia
Informazioni sul tipo di runtime Original: Runtime type information The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
type_info type_index (C++11)	bad_typeid bad_cast
Tipo tratti Original: Type traits The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Categorie di tipo primario Original: Primary type categories The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_void (C++11) is_array (C++11) is_pointer (C++11) is_enum (C++11) is_union (C++11) is_class (C++11) is_function (C++11)	is_object (C++11) is_scalar (C++11) is_compound (C++11) is_integral (C++11) is_floating_point (C++11) is_fundamental (C++11) is_arithmetic (C++11)
is_reference (C++11)
is_lvalue_reference (C++11)
is_rvalue_reference (C++11)
is_member_pointer (C++11)
is_member_object_pointer (C++11)
is_member_function_pointer (C++11)

Proprietà del tipo Original: Type properties The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_const (C++11) is_volatile (C++11) is_pod (C++11) is_empty (C++11) is_polymorphic (C++11) is_abstract (C++11)	is_trivial (C++11) is_trivially_copyable (C++11) is_standard_layout (C++11) is_literal_type (C++11) is_signed (C++11) is_unsigned (C++11)

Operazioni supportate Original: Supported operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_constructible is_trivially_constructible is_nothrow_constructible (C++11) (C++11) (C++11)
is_default_constructible is_trivially_default_constructible is_nothrow_default_constructible (C++11) (C++11) (C++11)
is_copy_constructible is_trivially_copy_constructible is_nothrow_copy_constructible (C++11) (C++11) (C++11)
is_move_constructible is_trivially_move_constructible is_nothrow_move_constructible (C++11) (C++11) (C++11)
is_assignable is_trivially_assignable is_nothrow_assignable (C++11) (C++11) (C++11)
is_copy_assignable is_trivially_copy_assignable is_nothrow_copy_assignable (C++11) (C++11) (C++11)
is_move_assignable is_trivially_move_assignable is_nothrow_move_assignable (C++11) (C++11) (C++11)
is_destructible is_trivially_destructible is_nothrow_destructible (C++11) (C++11) (C++11)
has_virtual_destructor (C++11)
I rapporti e le query di proprietà Original: Relationships and property queries The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_same (C++11) is_base_of (C++11) is_convertible (C++11)	alignment_of (C++11) rank (C++11) extent (C++11)
Tipo modifiche Original: Type modifications The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
remove_cv remove_const remove_volatile (C++11) (C++11) (C++11) add_cv add_const add_volatile (C++11) (C++11) (C++11) make_signed (C++11) make_unsigned (C++11)	remove_reference (C++11) add_lvalue_reference add_rvalue_reference (C++11) (C++11) remove_pointer (C++11) add_pointer (C++11) remove_extent (C++11) remove_all_extents (C++11)
Tipo di trasformazioni Original: Type transformations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
aligned_storage (C++11) aligned_union (C++11) decay (C++11) enable_if (C++11)	conditional (C++11) common_type (C++11) underlying_type (C++11) result_of (C++11)
Digitare costanti tratto Original: Type trait constants The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
integral_constant (C++11)

 

Elemento definito nell'header <cstddef>
typedef/*implementation-defined*/ ptrdiff_t;

std::ptrdiff_t è il tipo intero con segno del risultato della sottrazione dei due puntatori.

Original:

std::ptrdiff_t is the signed integer type of the result of subtracting two pointers.

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Note

std::ptrdiff_t è utilizzato per l'aritmetica dei puntatori e l'indicizzazione di array, se i valori negativi sono possibili. Programmi che utilizzano altri tipi, come int, può fallire su, ad esempio Sistemi a 64 bit, quando l'indice supera INT_MAX o se si basa su 32 bit aritmetica modulare.

Original:

std::ptrdiff_t is used for pointer arithmetic and array indexing, if negative values are possible. Programs that use other types, such as int, may fail on, e.g. 64-bit systems when the index exceeds INT_MAX or if it relies on 32-bit modular arithmetic.

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Quando si lavora con il C + + contenitore di libreria, il tipo corretto per la differenza tra gli iteratori è il difference_type membro typedef, che spesso è sinonimo di std::ptrdiff_t.

Original:

When working with the C++ container library, the proper type for the difference between iterators is the member typedef difference_type, which is often synonymous with std::ptrdiff_t.

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Solo i puntatori alle elementi della matrice stessa (compreso il puntatore uno oltre la fine della matrice) possono essere sottratti tra loro.

Original:

Only pointers to elements of the same array (including the pointer one past the end of the array) may be subtracted from each other.

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Se un array è così grande (maggiore di elementi PTRDIFF_MAX, ma meno di SIZE_MAX byte), che la differenza tra due puntatori non possono essere rappresentabile come std::ptrdiff_t, il risultato della sottrazione tali due puntatori è indefinito.

Original:

If an array is so large (greater than PTRDIFF_MAX elements, but less than SIZE_MAX bytes), that the difference between two pointers may not be representable as std::ptrdiff_t, the result of subtracting two such pointers is undefined.

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Per gli array char di lunghezza inferiore a PTRDIFF_MAX, std::ptrdiff_t funge da controparte firmata std::size_t: è in grado di memorizzare le dimensioni della matrice di qualsiasi tipo ed è, sulla maggior parte delle piattaforme, sinonimo di std::intptr_t).

Original:

For char arrays shorter than PTRDIFF_MAX, std::ptrdiff_t acts as the signed counterpart of std::size_t: it can store the size of the array of any type and is, on most platforms, synonymous with std::intptr_t).

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Esempio

#include <cstddef>int main(){conststd::size_t N =100;int* a = new int[N];int* end = a + N;for(std::ptrdiff_t i = N; i>0;--i)*(end - i)= i; delete[] a;   }

Vedi anche

size_t	senza segno tipo intero restituito dal gestore sizeof Original: unsigned integer type returned by the sizeof operator The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (typedef)
offsetof	byte offset dall'inizio di un layout di tipo standard per membro specificato Original: byte offset from the beginning of a standard-layout type to specified member The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (funzione macro)