External Variables:
External identifiers such as global variables and function names are declared with static storage duration
Global variables and function names are of storage class extern by default.
Global variables are created by placing variable declarations outside any function definition, and they retain their values throughout the execution of the program.
Global variables and functions can be referenced by any function that follows their declarations or definitions in the file.
In the ‘C’ program structure shown on the screen long value1 and int value4 are external variables.
Example:
#include<stdio.h>
#include<conio.h>
int v=10;
void main()
{
call1();
call2();
printf(“\n in main() V=%d”,v);
}
call1()
{
printf(“\n in call1() V=%d”,v);
}
call2()
{
printf(“\n in call2() V=%d”,v);
}
OUTPUT
In call1() V=10
In call2() V=10
In main() V=10
Explanation:
In this program variable ‘v’ is declared outside the function body and initialized to value 10. Evert function can access the variable ‘v’ so no re-declaration or local variable is created. Every function in turn prints the value of ‘v’. The same value is printed by all the functions.
