Programming in C Language

Introduction to Programming in C Language

C is general purpose structured programming language. It is the outcome of two

programming languages B and BCPL. All three programming languages were

developed at bell laboratory, USA. It is written by Dennis Ritchie & Brain Kernighan in

1978. C is both (1) System program and (2) Application program development tool. It

lies between high and lower level languages so it is also called as Middle level

language. The c character set consists of alphabets, digits, and special symbols.

There are 91 characters in C. The C tokens are the basic units of C program and they

are categorized into keywords, identifiers, constants, strings, operators and special

symbols. All the keywords in C have one or more fixed meaning and they can not be

changed. The keywords must be written in lowercase letters. The identifiers can not

be changed. The identifiers are the names given to the program elements such as

variables, arrays and functions. All the variables must be declared for their types

before they are used in the program. A constant is a quantity that does not change

during the execution of a program. A variable is a quantity that changes during the

execution of a program. Each instruction end with character semicolon “;” and

comments can be placed anywhere. All the words in a program line must be

separated from each other by at least one space or tab, or punctuation. Every C

program requires a main ( ) function and its place is where the program execution

begins. The execution of a function begins at the opening brace of the function and

ends at the corresponding closing brace. We must make sure to include header files

using # include directive when the program refers to special names and functions that

it does not define.