#include <blitz/array.h>using namespace blitz;       class Base {       public:         virtual void multiply(Array<int,1>& array) const=0;       };       class Derived1 : public Base {       public:         Derived1(){}         void multiply(Array<int,1>& array) const {array*=1;}       };       class Derived2 : public Base {       public:         Derived2(){}         void multiply(Array<int,1>& array) const {array*=2;}       };       Array<int,1>& operator*=(Array<int,1>& array, const Derived1& object) {         object.multiply(array);         return array;       }int main(){       Array<int,1> array(5);       array=1;       Derived1 derived1;       array*=derived1;}