#include 
    using namespace std;
    class Example 
    {
        int K;
        public:
        Example(int KK) : K(KK) {}
        const Example
        operator+(const Example& rv) const 
        {
            cout << "operator++" << endl;
            return Example(K + rv.K);
        }
        Example&
        operator+=(const Example& rv) 
        {
            cout << "operator++=" << endl;
            K += rv.K;
            return *this;
        }
    };
    int main() 
    {
        int K = 2, L = 3, k = 4;
        k += K + L;
        Example KK(2), LL(3), MM(4);
        MM += KK + LL;
    }