Data Structure

The term data means that value or set of values. It specifies either the value of a variable or a
constant (Such as – name of a student, marks of students, roll number of student, etc.).
A data item that does not have subordinate data items is categorized as an elementary item, it is composed of one or more subordinate data items is called a Group Item.

A record is a collection of data items.
For example – name, address, roll number, etc.
A file is a collection of related records.
For example – if there are 60 students in a class, then there are 60 records of the students. All these related records are stored in a file.

A data structure is the logical or mathematical arrangement of data in memory. It considers not only the physical layout of the data items in the memory but it is the relationships between the data items and the operations. Data structures are used in almost every program or software system.
For examples – Array, Stack, Queue, Linked list, Tree, Graph, Sorting, Searching and Hashing.