A programming language is a formal set of instructions for computers, used to create programs that solve problems. The document discusses the evolution of programming languages, focusing on 'C' developed by Dennis Ritchie in 1972, and explains its structure, components, and provides a sample program to calculate the area of a circle. It also covers tokens, keywords, data types, operators, and constants in 'C'.

1. PROGRAMMING IN ‘C’
What is meant by programming language?
A programming language is a formal
language which comprises a set of
instructions that produce various kinds
of output.
Most programming languages consist
of instructions for computers.
programming languages are used to create
programs to solve problems

2. About ‘c’
 Root of all modern languges is ALGOL-algorithmic
language in 1960s
 1967-BCPL-Basic Combined Programming Language
was developed
 Ken thompson created a language ‘B’
 ‘C’ was developed by Dennis Ritche in 1972
 ‘C’ is a structured programming language

3. STRUCTURE EXPLANATION
Documentation Consists of comments, some description of
the program.
Link Provides instruction to the compiler to Link
function from the library function.
Definition Consists of symbolic constants.
Global declaration Consists of function declaration and global
variables.
main( )
{
Declaration part;
executable part;
}
Every C program must have
main() function which is the starting
point of the program execution.
Subprograms
function 1
function 2
--
function n
User defined functions.

4. Sample program
/* Program to find the area of a circle using the radius r */
#include <stdio.h> /*link section-*/
#define PI 3.1416 /*definition section*/
float area; /*global declaration*/
main() /*main function starts here*/
{
float r ; /*local variable declaration*/
printf(“nEnter the value for r=”);
scanf(“%f”,&r); /*input statement*/
area = PI *r*r; /*assignment statement*/
printf(“nArea: %.2f", area); /*output statement*/
} /*main fun ends*/
Output:
Enter the value for r =10
The above code will give the following output.
Area: 314.16

5. C tokens
Tokens-individual words and punctuation marks
 Keyword: reserved words-32 keywords
 E.g static, int,printf,scanf
 Identifier-every c word is classified as either
keyword or identifier
 E.g main,amount
 Constants-fixed values
 Two types
 Numeric constants
 Integer constant ,real constant
 Character constants
 Single character constants, string constants

6. ---continued
 Strings
 Sequence of characters (E.g “welcome”)
 Operators
 8 types of operators
 Arithmetic operator-( +, -,*,/)
 Relational operator-(<,>,<=,>=,==,!=)
 Logical operator (AND &&,OR ||,NOT !)
 Assignment operator(=)
 Increment & decrement operator(++,- -)
 Conditional operator(?,: )
 Bit wise operator (bit wise&, bit wise |)
 Special operator (sizeof)
 Special symbols({ },[ ], ( ) )

8. Thank you