East const

    one consistent rule:
    What's left of const is constant.

    const West

    (still) more widespread,
    but less consistent

    int i = 1;
    int & r = i;
    int * p = &i;
    int const c = 1;
    int const& cr = i;
    // pointer to const int
    int const* pc = &i;
    // const pointer to int
    int *const cp = &i;
    // const pointer to const int
    int const*const cpc = &i;
    const int c = 1;
    const int& cr = i;
    // pointer to const int
    const int* pc = &i;
    // const pointer to int
    int *const cp = &i;
    // const pointer to const int
    const int *const cpc = &i;
    The concept name must appear directly before auto.
    #include <concepts>
    using std::regular;
    // type of 'a' must be "regular"
    regular auto   a = f(); 
    regular auto&  b = f(); 
    regular auto&& c = f();
    East const
    regular auto const  v = f();
    regular auto const& w = f();
    
    regular auto const* x = f();
    regular auto *const y = f();
    regular auto const*const z = f();
    const West
    const regular auto  v = f();
    const regular auto& w = f();
    
    const regular auto* x = f();
    regular auto *const y = f();
    const regular auto *const z = f();

    No difference between east and west const, but consistent with east const.

    // only callable on const values
    void MyClass::foo() const;
    
    // only callable on const lvalues 
    void MyClass::bar() const&;