Converting constructor - cppreference.com

struct A
{
    A() { }         // converting constructor (since C++11)  
    A(int) { }      // converting constructor
    A(int, int) { } // converting constructor (since C++11)
};

struct B
{
    explicit B() { }
    explicit B(int) { }
    explicit B(int, int) { }
};

int main()
{
    A a1 = 1;      // OK: copy-initialization selects A::A(int)
    A a2(2);       // OK: direct-initialization selects A::A(int)
    A a3{4, 5};    // OK: direct-list-initialization selects A::A(int, int)
    A a4 = {4, 5}; // OK: copy-list-initialization selects A::A(int, int)
    A a5 = (A)1;   // OK: explicit cast performs static_cast, direct-initialization

//  B b1 = 1;      // error: copy-initialization does not consider B::B(int)
    B b2(2);       // OK: direct-initialization selects B::B(int)
    B b3{4, 5};    // OK: direct-list-initialization selects B::B(int, int)
//  B b4 = {4, 5}; // error: copy-list-initialization selected an explicit constructor
                   //        B::B(int, int)
    B b5 = (B)1;   // OK: explicit cast performs static_cast, direct-initialization
    B b6;          // OK, default-initialization
    B b7{};        // OK, direct-list-initialization
//  B b8 = {};     // error: copy-list-initialization selected an explicit constructor
                   //        B::B()

    [](...){}(a1, a4, a4, a5, b5); // may suppress "unused variable" warnings
}