程序填空。下面的程序代码中中，Derived类是由基类Base1和Base2直接公有派生的，在它的set函数中，请把x1和x2的值依次初始化给属于基类Base1的x成员和属于基类Base2的x成员。classBaseBase{protected:intx;public:BaseBase(){x=1;}};classBase1:publicBaseBase{public:Base1(){}};classBase2:publicBaseBase{public:Base2(){}};classDerived:___1___{public:Derived(){}voidSet(intx1,intx2){___2__;___3___;}voidoutput(){cout<