DCA Access Standard Security Program (DASSP) On July 19, 2005, the Transportation Security Administration (TSA) released an interim final rule that allows certain general aviation aircraft to apply for access to Ronald Reagan Washington National Airport (DCA) under the DCA Access Standard Security Program (DASSP).
The basic operations that can be performed on a binary search tree data structure, are the following 1  â. Insert â Inserts an element in a tree/create a tree. 2  Search â Searches an element in a tree. 3  Preorder Traversal â Traverses a tree in a pre-order manner. 4  Inorder Traversal â Traverses a tree in an in-order manner.
In the pushdown stacks only two operations are allowed: push the item into the stack, and pop the item out of the stack. A stack is a limited access data structure - elements can be added and removed from the stack only at the top. push adds an item to the top of the stack, pop removes the item from the top. A helpful analogy is to think of a stack of books; you can remove only the top book, also you can add a new book on the top.