This document provides an introduction to programming in C, including key information about C as a programming language, its character set, tokens, identifiers, keywords, variable declaration and initialization, comments, and a simple example of a first C program. It outlines that C is a popular, structured, high-level language developed in 1972 that is efficient, fast, and supported across operating systems. It also describes the basic components and syntax of a C program, such as the main function, use of semicolons, and printf statement.

1. Programming in C (EST 102)
Jisu Elsa Jacob
Assistant Professor, ECE Dept. SCTCE

2. Introduction to Programming

3. C Programming
• Most popular computer languages
• Structured high-level language
• Developed by Dennis Ritchie in 1972
• Efficient and fast coding language
• Supported in all operating systems and hardwares
• Lots of compilers are available

4. Character set

5. Tokens in C
• Tokens are the smallest individual units in a program
• It includes:
• Identifiers –User specified names
• Keywords- With predefined meanings specific to C
• Constants – Fixed values like integer, character, float
• Strings – Sequence of characters
• Other symbols

6. IDENTIFIERS AND KEYWORDS
• Keywords have a specific meaning
• It has a predefined purpose
• Identifiers are names given to variables on our choice
• Keywords MUST NOT be used as identifiers

7. Identifiers
• An identifier refers to the name given to a variable or a
function.
• The rules to write an identifier name in C are:
❑Identifier name in C can have letters, digits or underscores.
❑The first character of an identifier name must be a letter or an
underscore. The first character of an identifier name cannot be a digit.
❑No special character (except underscore), blank space and comma can
be used in an identifier name.
❑Keywords or reserved words should not be used as identifier.

8. Keywords
• Keyword is a reserved word that has a particular meaning in
the programming language.
• The meaning of a keyword is predefined.
• A keyword cannot be used as an identifier name in C language.

9. Variable declaration and initialisation
int age; int age=20;

10. Comments
• A single-line comment starts with two forward slashes (i.e. //)
and is automatically terminated with the end of line.
• A multi-line comment starts with /* and terminates with */. A
multi-line comment is used when multiple lines of text are to be
commented.
• Comment lines are not executable statements and therefore
anything between /* and */ is ignored by the compiler

11. Introduction to programming
• Each statement should end with a semicolon
Eg: int a;
a=b+c;
• The execution begins at this line main(). The main( ) is a special
function used by the C system to tell the computer where the
program starts. Every program must have exactly one main function.

12. void main()
{
printf (“ Lets start C programming!!!”);
}
First C program
Compiler used in this lecture series is Dev-C++