Explain scope of a variable in C language.

Storage classes specify the scope, lifetime and binding of variables.

To fully define a variable, one needs to mention not only its ‘type’ but also its storage class.

A variable name identifies some physical location within computer memory, where a collection of bits are allocated for storing values of variable.

Storage class tells us the following factors −

Where the variable is stored (in memory or cpu register)?
What will be the initial value of variable, if nothing is initialized?
What is the scope of variable (where it can be accessed)?
What is the life of a variable?

Scope

Scope defines the visibility of an object. It defines where an object can be accessed.

The scope variable is local or global

The variable defined within the block has local scope. They are visible only to the block in which they are defined.
The variable defined in global area is visible from their definition until the end of program. It is visible everywhere in program.

Example

Following is the C program for the scope of a variable −

#include<stdio.h>
int c= 30; /* global area */
main ( ) {
   int a = 10; //local scope//
   printf ("a=%d,c=%d"a,c);
   fun ( );
}
fun ( ){
   printf ("c=%d",c); //global variable
}

Output

When the above program is executed, it produces the following output −

a =10, c = 30
c = 30

Example

Following is the C program for the local and global variables −

Live Demo

#include<stdio.h>
int a,b;
a=1,b=2;
main() {
   int c,d;
   printf("enter c and d values:");
   scanf("%d%d",&c,&d);
   c=c+d; //local variables
   b=a*b; //global variables
   printf("c value is:%d\n",c);
   printf("b value is:%d\n",b);
}

Output

When the above program is executed, it produces the following output −

enter c and d values:4 7
c value is:11
b value is:2

Bhanu Priya

Published on 25-Mar-2021 08:07:21

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