3. Suppose you have a linked list structure and a node structure defined as follows: template class llist { lnode *header; llist() { header = new lnode(T()); header->prev = header; header->next = header; } void eraseAll(const T& target); };

template struct lnode { T val; lnode* next; lnode* prev; lnode(const T& x, lnode* y=NULL, lnode* z=NULL) : val(x), next(y), prev(z) {} };

Write the llist member function eraseAll, which takes a value target and erases all occurrences of target in the list.