introduction to learning objective this book deals with the study of data structures through before going into detailed analysis of data structuresit would be useful to familiarize ourselves with the basic knowledge of programming in thereforein this we will learn about the various constructs of such as identifiers and keywordsdata typesconstantsvariablesinput and output functionsoperatorscontrol statementsfunctionsand pointers introduction the programming language 'cwas developed in the early by dennis ritchie at bell laboratories although was initially developed for writing system softwaretoday it has become such popular language that variety of software programs are written using this language the greatest advantage of using for programming is that it can be easily used on different types of computers many other programming languages such as +and java are also based on which means that you will be able to learn them easily in the future todayc is widely used with the unix operating system structure of program program contains one or more functionswhere function is defined as group of statements that perform well-defined task figure shows the structure of program the statements in function are written in logical sequence to perform specific task the main(function is the most important function and is part of every program ratherthe execution of program begins with this function from the structure given in fig we can conclude that program can have any number of functions depending on the tasks that have to be performedand each function can have any number