std:: regular

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';
}

Equal
4 4

References

See also