Exchange of information through the use of speech, signs or symbols is called communication. When early humans started speaking, some 5,00,000 years ago, that was the first mode of communication. Before we dive into modern technologies that drive communication in contemporary world, we need to know how humans developed better communication techniques to share knowledge with each other.

Data Structures are the programmatic way of storing data so that data can be used efficiently. Almost every enterprise application uses various types of data structures in one or the other way.

An algorithm is a representation of a solution to a problem. If a problem can be defined as a difference between a desired situation and the current situation in which one is, then a problem solution is a procedure, or method, for transforming the current situation to the desired one. We solve many such trivial problems every day without even thinking about it, for example making breakfast, travelling to the workplace etc. But the solution to such problems requires little intellectual effort and is relatively unimportant. However, the solution of a more interesting problem of more importance usually involves stating the problem in an understandable form and communicating the solution to others. In the case where a computer is part of the means of solving the problem, a procedure, explicitly stating the steps leading to the solution, must be transmitted to the computer. This concept of problem solution and communication makes the study of algorithms important to computer science.

Computer System=Software+Hardware Computer Software Set of instructions that tells the hardware what to do, how to do it, and even when.

Building data structures and algorithms requires that we communicate detailed instructions to a computer. An excellent way to perform such communication is using a high-level computer language, such as Java. In this chapter, we provide an overview of the Java programming language, and we continue this discussion in the next chapter, focusing on object-oriented design principles. We assume that readers are somewhat familiar with an existing high-level language, although not necessarily Java. This book does not provide a complete description of the Java language (there are numerous language references for that purpose), but it does introduce all aspects of the language that are used in code fragments later in this book.

Java is an object-oriented, class-based, concurrent, secured and general-purpose computer-programming language which is a widely used and a robust technology. What is Java-Java is a programming language and a platform. • It is a high level, robust, secured and object-oriented programming language. • It is also a Platform: A platform is any hardware or software environment in which a program runs. Remember Operating Systems are softwares that runs on hardware platforms, But Os also acts as platforms on which applications runs.

Introduction – Remember Linear List • Array ( Done) – Search, Modification,Insertion, Deletion – Flow chart and Pseudo-codes – Implementation – Any Question • Linked List ( Today) • Stacks • Queues

A tree is a nonlinear data structure used to represent entities that are in some hierarchical relationship • Examples in real life: • Family tree • Table of contents of a book • Class inheritance hierarchy in Java • Computer file system (folders and subfolders) • Decision trees • Top-down design

A set is a collection of non repeating objects. • The objects in a set are called its elements or members. • The elements in a set can be any types, including sets(set of sets)! The members of a set do not even have to be of the same type. Fo • forr example, a set can consist of numbers and names

Data Structure MCQ 1) How can we describe an array in the best possible way? a. The Array shows a hierarchical structure. b. Arrays are immutable. c. Container that stores the elements of similar types d. The Array is not a data structure Hide Answer Workspace Answer: c Explanation: The answer is c because array stores the elements in a contiguous block of memory of similar types. Therefore, we can say that array is a container that stores the elements of similar types