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std::regular

Defined in header `<concepts>`
template <class T> concept regular = std::semiregular<T> && std::equality_comparable<T>;		(since C++20)

The regular concept specifies that a type is regular, that is, it is copyable, default constructible, and equality comparable. It is satisfied by types that behave similarly to built-in types like int, and that are comparable with ==.

Example

#include <concepts>
#include <iostream>
 
template<std::regular T>
struct Single {
    T value;
    friend bool operator==(const Single&, const Single&) = default;
};
 
int main()
{
    Single<int> myInt1{4};
    Single<int> myInt2;
    myInt2 = myInt1;
 
    if (myInt1 == myInt2)
        std::cout << "Equal\n";
 
    std::cout << myInt1.value << ' ' << myInt2.value << '\n';
}

Output:

Equal
4 4

std::regular

Example

See also