Scope Rules in C

Scope Rules in C:

Scope rules in C or scope of a variable means that from where the variable may directly be accessible after its declaration.
The scope of a variable in C programming language can be declared in three places :

Scope	Place
Local Variable	Inside a function or block
Global variable	Outside of all function(can be accessed from anywhere)
Formal Parameters	In the function parameters

Local variable: Local variables are the variables that are declared inside a block or a function.
These variables can only be used inside that block or function.
Local variables can’t be accessed from outside of that block or function.

Example :

#include <stdio.h>
int main()
{
  /* Declaration of local variable  */

int a;
/* initialization */
a = 7;
printf (“value of a = %d\n”, a);
return 0;
}

Output :

value of a = 7

Global Variable: Global variable is the variable that is declared outside of a block or function. These variables can be accessed from anywhere in the program.

Once a global variable is declared you can use it throughout your entire program.

Example :

#include <stdio.h>
 /* Declaration of global variable  */

int a;
int main()
{

/* initialization */
a = 7;
printf (“value of a = %d\n”, a);
return 0;
}

Output :

value of a = 7

Formal parameter: Formal parameters are the parameter that are written in the function definition.
Formal parameter takes precedence over global variable.