The document discusses storage classes in C programming. It defines storage class as containing both a variable's datatype and storage location. The four main storage classes are automatic, register, static, and external. Automatic variables are allocated on the stack and deleted after function call. Register variables are stored in processor registers for faster access. Static variables retain their value between function calls. External variables can be accessed from other source files. Examples are provided to illustrate each storage class.

1. Storage Class
Programming Techniques using C
Under the guidance of
Mrs. Sushma Mishra
Submitted by:
Joyce Aiman Parhi
BCA 2nd Semester
Roll no. 20

2. What is a Storage Class?
Each variable declared in C contains not only a datatype but
a storage class too. If the programmer does not write it explicitly, the C
preprocessor expands the line of code and adds the default storage class
keyword i.e. ‘auto’ to the statement.

3. Types
● Automatic
● Register
● Static
● External

4. Features
● Storage
● Life
● Scope
● Default Value

5. extern
Storage Class
int
Datatype
i
Variable Name
=
Assignment Operator
20
Value
Syntax

6. Example’s

7. auto
#include<stdio.h>
#include<conio.h>
void main()
{
auto int i; /* default storage class i.e.
auto */
int a,b; /* Same as writing ‘auto int’
a */
for(i=0;i<100;i++)
{
printf("Hellon");
}
getch();
}

8. register
#include<stdio.h>
#include<conio.h>
void main()
{
int a,b; /* */
register int i; /* */
for(i=0;i<100;i++)
{
printf("Hellon");
}
getch();
}

9. static
#include<stdio.h>
#include<conio.h>
void main()
{
int a,b; /* */
static int i; /* */
for(i=0;i<100;i++)
{
printf("Hellon");
}
getch();
}

10. extern
#include<stdio.h>
#include<conio.h>
void main()
{
int a,b; /* */
extern int i; /* */
for(i=0;i<100;i++)
{
printf("Hellon");
}
getch();
}

11. Thank You