std::ranges::views::cartesian_product, std::ranges::cartesian_product_view - cppreference.com (original) (raw)

std::ranges::cartesian_product_view

1. cartesian_product_view is a range adaptor that takes n views, where n > 0, and produces a view of tuples calculated by the n-ary cartesian product of the provided ranges. The size of produced view is a multiple of sizes of provided ranges, while each element is a tuple (of references) of the size n.

2. Determines if cartesian_product is a random access range (see also random_access_range).

3. Determines if cartesian_product is a common range (see also common_range).

4. Determines if cartesian_product is a bidirectional range (see also bidirectional_range).

5. Determines if cartesian_product satisfies the helper concept /*cartesian-product-is-common*/ (see also common_range).

6. Determines if cartesian_product is a sized range (see also sized_range).

7. Determines if cartesian_product uses sized sentinel.

8. Returns the end of the produced view. Participates in overload resolution only if cartesian_product satisfies the helper concept /*cartesian-product-common-arg*/.

The First range passed to cartesian_product_view is treated specially, since it is only passed through a single time. As a result, several constrains are relaxed on it:

• First is an input_range instead of forward_range;
• First does not have to be a sized_range in order for the cartesian_product_view to be random_access_range or common_range;
• First does not have to be common_range in order for the cartesian_product_view to be bidirectional_range.

Contents

• 1 Customization point objects
• 2 Data members
• 3 Member functions
  • 3.1 Inherited from std::ranges::view_interface
• 4 Deduction guides
• 5 Nested classes
• 6 Notes
• 7 Example
• 8 References
• 9 See also

Customization point objects

The name views::cartesian_product denotes a customization point object, which is a const function object of a literal semiregular class type. See CustomizationPointObject for details.

[edit] Data members

[edit] Member functions

[edit] Deduction guides

[edit] Nested classes

| | the iterator type(exposition-only member class template*) | | ------------------------------------------------------------- |

[edit] Notes

[edit] Example

#include #include #include #include #include #include   void print(std::tuple<char const&, int const&, std::string const&> t, int pos) { const auto& [a, b, c] = t; std::cout << '(' << a << ' ' << b << ' ' << c << ')' << (pos % 4 ? " " : "\n"); }   int main() { const auto x = std::array{'A', 'B'}; const auto y = std::vector{1, 2, 3}; const auto z = std::list<std::string>{"α", "β", "γ", "δ"};   for (int i{1}; auto const& tuple : std::views::cartesian_product(x, y, z)) print(tuple, i++); }

Output:

(A 1 α) (A 1 β) (A 1 γ) (A 1 δ) (A 2 α) (A 2 β) (A 2 γ) (A 2 δ) (A 3 α) (A 3 β) (A 3 γ) (A 3 δ) (B 1 α) (B 1 β) (B 1 γ) (B 1 δ) (B 2 α) (B 2 β) (B 2 γ) (B 2 δ) (B 3 α) (B 3 β) (B 3 γ) (B 3 δ)

[edit] References

• C++23 standard (ISO/IEC 14882:2024):

• 26.7.31 Cartesian product view [range.stride]

[edit] See also