binary tree breadth first traversal in c++

BFS is faster to find shortest path from root to leaf node of a tree. But the tradeoff is to use more memory. 

the basic trategy is to maintain a list to hold nodes of each level. 

void BFS(TreeNode<T>* node){
   if(node == NULL) // if node is NULL, return
      return;
  else{
     std::list<TreeNode<T>* > current;
     current.push_back(node);
     while( current.size != 0){
        std::list<TreeNode<T>* > next_level;
        for(std::list<TreeNode<T>* >::iterator itr = current.beign();
              itr != current.end(); ++itr){
           if(node->left) next_level.push_back(node->left);
           if(node->right) next_level.push_back(node->right);
        }
        current = next_level;
    }  
  }   
}

you could use iterator to traverse the current list to print out the values as well.