C Variable Scope

Functions

C Variable Scope

A scope is a region of the program, and the scope of variables refers to the area of the program where the variables can be accessed after its declaration.

n C programming, variable declared within a function is different from a variable declared outside a function.

C programming variables can be declared in three places:

Position	Type
Inside a function or a block.	local variables
Out of all functions.	Global variables
In the function parameters.	Formal parameters

Local Variables

Variables that are declared within the function block and can be use only within the function is called local variables.

Example:

#include <stdio.h>
 
int main ()
{
    /* local variable definition and initialization */
    int x,y,z;
     
    /* actual initialization */
    x = 20;
    y = 30;
    z = x + y;
     
    printf ("value of x = %d, y = %d and z = %d\n", x, y, z);
     
    return 0;
}

Global Variables

Variables that are declared outside of a function block and can be accessed inside the function is called global variables.

Example:

#include <stdio.h>

/* global variable definition */
int z;

int main ()
{
    /* local variable definition and initialization */
    int x,y;
     
    /* actual initialization */
    x = 20;
    y = 30;
    z = x + y;
     
    printf ("value of x = %d, y = %d and z = %d\n", x, y, z);
     
    return 0;
}