#include <boost/contract.hpp>
#include <cassert>

//[volatile
class a {
public:
    void invariant() const volatile;    // Invariants cv qualified.
    void invariant() const;             // Invariants const qualified.

    a() { // Check both cv and const invariant (at exit if no throw).
        boost::contract::guard c= boost::contract::constructor(this);
    }

    ~a() { // Check both cv and const invariant (at entry).
        boost::contract::guard c = boost::contract::destructor(this);
    }

    void m() { // Check const invariant (at entry and exit if no throw).
        boost::contract::guard c = boost::contract::public_function(this);
    }

    void c() const { // Check const invariant (at entry and exit if no throw).
        boost::contract::guard c = boost::contract::public_function(this);
    }
    
    void v() volatile { // Check cv invariant (at entry and exit if no throw).
        boost::contract::guard c = boost::contract::public_function(this);
    }
    
    void cv() const volatile { // Check cv inv. (at entry and exit if no throw).
        boost::contract::guard c = boost::contract::public_function(this);
    }
};
//]

bool cv_invariant_checked, const_invariant_checked;
void a::invariant() const volatile { cv_invariant_checked = true; }
void a::invariant() const { const_invariant_checked = true; }

int main() {
    {
        cv_invariant_checked = const_invariant_checked = false;
        a x;
        assert(cv_invariant_checked);
        assert(const_invariant_checked);

        cv_invariant_checked = const_invariant_checked = false;
        x.m();
        assert(!cv_invariant_checked);
        assert(const_invariant_checked);
        
        cv_invariant_checked = const_invariant_checked = false;
        x.c();
        assert(!cv_invariant_checked);
        assert(const_invariant_checked);
        
        cv_invariant_checked = const_invariant_checked = false;
        x.v();
        assert(cv_invariant_checked);
        assert(!const_invariant_checked);
        
        cv_invariant_checked = const_invariant_checked = false;
        x.cv();
        assert(cv_invariant_checked);
        assert(!const_invariant_checked);
    
        cv_invariant_checked = const_invariant_checked = false;
    } // Call destructor.
    assert(cv_invariant_checked);
    assert(const_invariant_checked);

    return 0;
}