Storage Classes in C language defines the Scope of the Variable in the Entire program.
There are 4 Storage Classes in C language :
1.auto
2.register
3.static
4.extern
1.auto:
-By default , for every local variable auto class is selected.
Syntax-
int var;
or
auto int var;
Above both way is correct to define a auto variable.
2.register:
-By using this class, variable can store in directly in register instead of the RAM.
Syntax-
register type variable;
Example-
register int a;
register float b;
register char c;
3.static :
- By using this class, the existance of the local variable is become the life time of the program.
Syntax-
static type variable
4.extern :
-By using this class, the scope of the variable is become widely. means we can excess this variable from anywhere in the entire program.
program-
#include< stdio.h>
int main()
{
#include
int main()
{
auto int a=1;
static int b=2;
register int c=3;
extern int d=4;
printf("%d\n",a);
printf("%d\n",b);
printf("%d\n",c);
printf("%d\n",d);
}
output-
1
2
3
4