Getting an error "=" no operator matches, I am trying to add object to dynamic array

DOG  *dog_container = new DOG[100];

void add_DOG(string dn){
    
    int size = sizeof(dog_container)/sizeof(dog_container[0]);
    Company *toADDdog = new Company(dog);
    do_container[size]=toADDdog;------/// ?? I am getting errors here

}

Can someone help me explain how I can add an object in the dynamic array if the function is add_Dog into a container which is Dynamic container,