The SequentialSearchST class represents an (unordered) symbol table of generic key-value pairs. It supports the usual Put, Get, Indexer, Contains, Delete, Count, and IsEmpty methods. It also provides a Keys method for iterating over all of the keys. A symbol table implements the Associative array abstraction: when associating a value with a key that is already in the symbol table, the convention is to replace the old value with the new value. The class also uses the convention that values cannot be null. Setting the value associated with a key to null is equivalent to deleting the key from the symbol table.

This implementation uses a singly-linked list and sequential search. It relies on the Equals() method to test whether two keys are equal. It does not call either the CompareTo() or GetHashCode() method. The Put and Delete operations take linear time; the Get and Contains operations takes linear time in the worst case. The Count, and IsEmpty operations take constant time. Construction takes constant time.