C is a general-purpose programming language that is widely used for developing system software and applications. Some key aspects of C include: 1) C code is made up of functions that contain statements to be executed. Functions in C can be declared as global, accessible anywhere, or local, only accessible within the block they are defined. 2) C supports basic data types like integers, floats, characters, and strings. Variables are declared with a specific data type and can be defined as global or local. 3) The main() function is the entry point of every C program. It contains the primary logic to be executed. Header files contain declarations that are included using #include directives.

1. 2
C
C Denis Ritchie
1970
UNIX)
C
C Middle –lever
language)
C compiled Language)
(Compiler) Compile)
Machine Language)
C
C

2. Int main (void)
{
Header Files)
C
#include< >
#include “ ”
#include<stdio.h>

3. h
1
stdio.h
Global (Global Variables)
Functions)
C 1
Main() 1
1
Local (Local Variables)
(Statements)
C ;

4. C
C
Case Sensitive
Test, test C
;
Return Value)
Comment)

5. 2-2 Comment
2 – 1
Identifier)
1. _
2. 2 _
3. _
4. 31
5.
6. C

6. A $sum
Student_name Student Name
_SystemName 2names
A1 int
C
C
C 4
Void Type (Void)
Integer Type (int)
C
3 short int,int long int
2-1
Short int 2 16 -32,768 32,768
0 65,535

7. Int 2 16 -32,768 32,768
(16 0 65,535
Int 4 32 - 2,147,486,643
(32 2,147,486,643 4,294,967,295
0
Long int 4 32 - 2,147,486,643
2,147,486,643 4,294,967,295
0
Character Type (char)
A-Z 0-9
ACSII (American Standard Code Information Interchange)
1
127
1 8
Floating Point Type (flat)
3 float,
double long double
2-2
2-2
float 4 32 -38 38

8. 3.4-10 3.4-10
double 8 64 -
308 308
1.7*10 1.7*10
long double 10 80 -
4932 4932
3.4*10 1.1*10
C 2
Global
Local
#include<stdio.h>
int total; /* Global */
main()
{
int price,money; /* Local*/

9. …
}
2-3
int total = 0;
int total =0,sum
int total =0,sum=0;
total = 50;
total = total+sum
scanf(“%d”,&total);

10. 2-2
#include<stdio.h>
/* Global*/
int sum = 0;
int main(void)
{
/* Local */
int a;
int b;
int c;
/*
printf(“nWelcome. This Program addsn”);
printf(“threenumbers.Enter three numbersn”);
printf(“in the form: nnn nnn nnn <retur>n”);
scanf(“%d %d %d”,&a,&b,&c);
/* a,b c sum*/
sum=a+b+c;

11. printf(“The total is: %dn”,sum);
printf(“Thant you. Have a good day.n”);
return 0;
}
Welcome. This Program adds
Three numbers. Enter three number
In the form: nnn nnn nnn <return>
11 22 23
The total is: 56
Thank you. Have a good day.
([

12. (float)a
(int)a
2-3
#include<stdio.h>
int main(void)
{
float a= 25.3658;
printf(“Value of a : %n”,a);
printf(“Value of a when set is integer : %dn”,(int)a);
return 0;
}
Value of a : 25.365801
Value of a when change is integer : 25
Constants)
Constants

13. Const[
const folat a = 5.23;
const int b = a%2;
2-4
#include<stdio.h>
imt main(void)
{
const float pi = 3.14159;
float radius;
radius = 3;
printf(“Value of pi : %fn”,pi);
printf(“Value of area : %fn”,pi*(radius*radius));
return 0;
}
Value of pi : 3.141590
Value of area : 28.274311

14. constant
Integer Constants
const int a = 5;
Floating-Point Constants
const float b = 5.6394;
Character Constants
‘’
const char b = ‘t’;
String Constants
“”
“”
“h”
“Hello worldn”
“HOW ARE YOU”
“Good Morning!”
2-5
#includ<stdio.h>
int main(void)

15. {
const int a = 3; /*Integer Constats*/
const flat b = 3.14159; /*Floating – Point Constants*/
const cahr c = ‘P’; /*Character Constants*/
printf(“Value of a: %dn”,a);
printf(“Value of b: %dn”,b);
printf(“Value of c: %dn”,c);
printf(“Good Bye”); /*String Constants*/
return 0;
}
Value of a : 3
Value of b : 3.141590
Value of c : P
Good Bye
Statements
statements c

16. c 6
Expression Statement Compound Statement 2
1. Expression Statement Single Statement
Statement ; statement
C ;
Statement
a = 2;
printf(“x contains %d, y contains %dn”,x,y);
Compound Statement Block
{ }
Statement Main
C Compound Statement
Flowchart)

17. 1.
Terminator
2.
Process
3.
Decision
4.
Data
5.
Manual Input

18. 6.
Display
7.
Predefined Process
8.
Connect
9.
Arrow
3
1.

19. 2.

20. if…else
3.
do….while