当我尝试编译以下代码时:classA{public:A(intv):virt(v){}intvirt;intgetVirt(void)const{returnvirt;}};classB:privatevirtualA{protected:B(intv):A(v){}usingA::getVirt;};classC:publicB,privatevirtualA{protected:C(intv):A(v),B(v){}usingA::getVirt;};classD:publicC{public:D(void):C(3){}usingC::getVirt;};#includeintm