编译时有理数算术

类型特性

类型类别

is_void (C++11)
is_null_pointer (C++14)
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)

类型属性

is_const

(C++11)

is_volatile

(C++11)

is_empty

(C++11)

is_polymorphic

(C++11)

is_final

(C++14)

is_abstract

(C++11)

is_aggregate

(C++17)

is_trivial

(C++11)

is_trivially_copyable

(C++11)

is_standard_layout

(C++11)

is_literal_type

(C++11)(C++20 前)

is_pod

(C++11)(C++20 中弃用)

is_signed

(C++11)

is_unsigned

(C++11)

is_bounded_array

(C++20)

is_unbounded_array

(C++20)

is_scoped_enum

(C++23)

has_unique_object_representations

(C++17)

类型特性常量

integral_constantbool_constanttrue_typefalse_type

(C++11)(C++17)(C++11)(C++11)

元函数

conjunction

(C++17)

disjunction

(C++17)

negation

(C++17)

受支持操作

is_constructibleis_trivially_constructibleis_nothrow_constructible (C++11)(C++11)(C++11)
is_default_constructibleis_trivially_default_constructibleis_nothrow_default_constructible (C++11)(C++11)(C++11)
is_copy_constructibleis_trivially_copy_constructibleis_nothrow_copy_constructible (C++11)(C++11)(C++11)
is_move_constructibleis_trivially_move_constructibleis_nothrow_move_constructible (C++11)(C++11)(C++11)
is_assignableis_trivially_assignableis_nothrow_assignable (C++11)(C++11)(C++11)

is_copy_assignableis_trivially_copy_assignableis_nothrow_copy_assignable (C++11)(C++11)(C++11)
is_move_assignableis_trivially_move_assignableis_nothrow_move_assignable (C++11)(C++11)(C++11)
is_destructibleis_trivially_destructibleis_nothrow_destructible (C++11)(C++11)(C++11)
has_virtual_destructor (C++11)
is_swappable_withis_swappableis_nothrow_swappable_withis_nothrow_swappable (C++17)(C++17)(C++17)(C++17)

关系与属性查询

is_same (C++11)
is_base_of (C++11)
is_convertibleis_nothrow_convertible (C++11)(C++20)
is_layout_compatible (C++20)
is_pointer_interconvertible_base_of (C++20)
is_pointer_interconvertible_with_class (C++20)
is_corresponding_member (C++20)

alignment_of (C++11)
rank (C++11)
extent (C++11)
is_invocableis_invocable_ris_nothrow_invocableis_nothrow_invocable_r (C++17)(C++17)(C++17)(C++17)

类型修改

remove_cvremove_constremove_volatile (C++11)(C++11)(C++11)
add_cvadd_constadd_volatile (C++11)(C++11)(C++11)
make_signed (C++11)
make_unsigned (C++11)

remove_reference (C++11)
add_lvalue_referenceadd_rvalue_reference (C++11)(C++11)
remove_pointer (C++11)
add_pointer (C++11)
remove_extent (C++11)
remove_all_extents (C++11)

类型变换

aligned_storage (C++11)
aligned_union (C++11)
decay (C++11)
remove_cvref (C++20)
enable_if (C++11)
void_t (C++17)

conditional (C++11)
common_type (C++11)
common_reference (C++20)
underlying_type (C++11)
result_ofinvoke_result (C++11)(C++20 前)(C++17)
type_identity (C++20)

编译时有理数算术

编译时整数序列

integer_sequence

(C++14)

编译时有理数算术

ratio (C++11)
算术
ratio_add (C++11)
ratio_subtract (C++11)
ratio_multiply (C++11)
ratio_divide (C++11)
比较
ratio_equal (C++11)
ratio_not_equal (C++11)
ratio_less (C++11)
ratio_less_equal (C++11)
ratio_greater (C++11)
ratio_greater_equal (C++11)

类模板 std::ratio 及相关的模板提供编译时有理数算术支持。此模板的每个实例化都准确表示任一有限有理数。

编译时分数

在标头 `<ratio>` 定义
ratio	表示准确的分数 (类模板)

标准库为提供数种对应 SI 比例的便利 typedef ：

在标头 `<ratio>` 定义
类型	定义
`yocto`	std::ratio<1, 1000000000000000000000000> ，若 std::intmax_t 能表示分母
`zepto`	std::ratio<1, 1000000000000000000000> ，若 std::intmax_t 能表示分母
`atto`	std::ratio<1, 1000000000000000000>
`femto`	std::ratio<1, 1000000000000000>
`pico`	std::ratio<1, 1000000000000>
`nano`	std::ratio<1, 1000000000>
`micro`	std::ratio<1, 1000000>
`milli`	std::ratio<1, 1000>
`centi`	std::ratio<1, 100>
`deci`	std::ratio<1, 10>
`deca`	std::ratio<10, 1>
`hecto`	std::ratio<100, 1>
`kilo`	std::ratio<1000, 1>
`mega`	std::ratio<1000000, 1>
`giga`	std::ratio<1000000000, 1>
`tera`	std::ratio<1000000000000, 1>
`peta`	std::ratio<1000000000000000, 1>
`exa`	std::ratio<1000000000000000000, 1>
`zetta`	std::ratio<1000000000000000000000, 1> ，若 std::intmax_t 能表示分子
`yotta`	std::ratio<1000000000000000000000000, 1> ，若 std::intmax_t 能表示分子