What is external storage class ?

External Storage Class is a type of storage class. Extern storage class variables are stored in memory. The default initial value of extern storage class variables is 0 (zero), unless they are initialized explicitly.

The scope of extern storage class variables is global, and the life time of the variable, persists as long as the program’s execution doesn’t come to an end.

Ex:

#include<stdio.h>

#include<conio.h>

void increment();

void decrement();

int x = 10;

void main( )

{

printf ( "\n X = %d", x ) ;

increment( ) ;

increment( ) ;

decrement( ) ;

decrement( ) ;

}

void increment( )

{

x = x + 1 ;

printf ( "\n After Increment x = %d", x ) ;

}

void decrement( )

{

x = x - 1 ;

printf ( "\n After Decrement x = %d", x ) ;

}

Output:

x = 10

After Increment x = 11

After Increment x = 12

After Decrement x = 11

After Decrement x = 10