43     explicit cpp20_iterator(T* ptr) : my_ptr(ptr) {}  in cpp20_iterator()
45     T& operator*() const { return *my_ptr; }  in operator *()
48         ++my_ptr;  in operator ++()
61         --my_ptr;  in operator --()
76         my_ptr += n;  in operator +=()
83         my_ptr -= n;  in operator -=()
90         return my_ptr[n];  in operator []()
101         return cpp20_iterator(i.my_ptr + n);  in operator +()
113         return cpp20_iterator(i.my_ptr - n);  in operator -()
117         return x.my_ptr - y.my_ptr;  in operator -()
120     T* my_ptr = nullptr;  member