- A data structure is a way of organizing data that considers not only the items stored, but also their relationship to each other. Advance knowledge about the relationship between data items allows designing of efficient algorithms for the manipulation of data. the logical and mathematical model of a particular organization of data is called data structure. There are two types of data structure
- Linear
- Nonlinear

- Compiler Design,
- Operating System,
- Database Management System,
- Statistical analysis package,
- Numerical Analysis,
- Graphics,
- Artificial Intelligence,
- Simulation

- RDBMS = Array (i.e. Array of structures)
- Network data model = Graph
- Hierarchical data model = Trees

- The heterogeneous linked list contains different data types in its nodes and we need a link, pointer to connect them. It is not possible to use ordinary pointers for this. So we go for void pointer. Void pointer is capable of storing pointer to any type as it is a generic pointer type.

- Two. One queue is used for actual storing of data and another for storing priorities.

- Stack. Because of its LIFO (Last In First Out) property it remembers its 'caller' so knows whom to return when the function has to return. Recursion makes use of system stack for storing the return addresses of the function calls. Every recursive function has its equivalent iterative (non-recursive) function. Even when such equivalent iterative procedures are written, explicit stack is to be used.

- Polish and Reverse Polish notations.

- Prefix Notation: - * +ABC ^ - DE + FG
- Postfix Notation: AB + C * DE - FG + ^ -

- Sorting is not possible in Deletion. Using insertion we can perform insertion sort, using selection we can perform selection sort, using exchange we can perform the bubble sort (and other similar sorting methods). But no sorting method can be done just using deletion.

- Straight merging,
- Natural merging,
- Polyphase sort,
- Distribution of Initial runs.

- The manipulation of Arithmetic expression,
- Symbol Table construction,
- Syntax analysis.

- Sparse matrix,
- Index generation.

- Linked list is the suitable efficient data structure.

- Backtracking.

- If the 'pivotal value' (or the 'Height factor') is greater than 1 or less than -1.

- One. If there is only one entry possible in the bucket, when the collision occurs, there is no way to accommodate the colliding value. This results in the overlapping of values.

- Direct method,
- Subtraction method,
- Modulo-Division method,
- Digit-Extraction method,
- Mid-Square method,
- Folding method,
- Pseudo-random method.

- Open addressing (closed hashing), The methods used include: Overflow block.
- Closed addressing (open hashing), The methods used include: Linked list, Binary tree.

- B+ tree. Because in B+ tree, all the data is stored only in leaf nodes, that makes searching easier. This corresponds to the records that shall be stored in leaf nodes.

- A spanning tree is a tree associated with a network. All the nodes of the graph appear on the tree once. A minimum spanning tree is a spanning tree organized so that the total edge weight between nodes is minimized.

- No. The Minimal spanning tree assures that the total weight of the tree is kept at its minimum. But it doesn't mean that the distance between any two nodes involved in the minimum-spanning tree is minimum.

- Sequential is the simplest file structure.

- According to Access strategies Linked list is a linear one.
- According to Storage Linked List is a Non-linear one.

- A linked list is a linear collection of data elements, called nodes, where the linear order is given by pointers. Each node has two parts first part contain the information of the element second part contains the address of the next node in the list.

- A queue is an ordered collection of items from which items may be deleted at one end (front end) and items inserted at the other end (rear end). It obeys FIFO rule there is no limit to the number of elements a queue contains.