vector<bool, A>::reference

class reference {
public:
    reference& operator=(const reference& x);
    reference& operator=(bool x);
    void flip();
    bool operator~() const;
    operator bool() const;
    };

The type describes an object that can serve as a reference to an element of the controlled sequence. Specifically, for two objects x and y of class reference:

• bool(x) yields the value of the element designated by x
• ~x yields the inverted value of the element designated by x
• x.flip() inverts the value stored in x
• y = bool(x) and y = x both assign the value of the element designated by x to the element designated by y

It is unspecified how member functions of class vector<bool, A> construct objects of class reference that designate elements of a controlled sequence. The default constructor for class reference generates an object that refers to no such element.