A variable is a name of a storage location where data gets stored. Using that name one can perform operations and manipulations on the values.

• A variable should not be named after a reserved keyword.
• Unlike constants, a variable holding value can be changed at runtime.

Each and every variable has a lifetime to which extent it is visible within a particular block called scope, and outside of that block, the variable doesn’t have any existence.

These variables can be categorised in local, global and static.

In this article, we mainly focus on global and local variable.

Scope: A scope can be defined as an area to which a variable,method, class and interface is visible.

In C, if we compare local and global variable there are the following differences:

Difference between Local variable and Global variable in Tabular form

Local Variable

A local variable is declared inside a function or a block and its scope is always limited to that particular function or block. It remains alive until that particular block or function completes its execution.

Local variables are local to a block or function and go out of scope at the time exiting from the block or curly braces ({}).

Global Variable

Global variables is a variable that is accessible to entire program and is available to all the functions or blocks. It can be accessible to all the functions in a program.

Therefore, two or more variables can have same name but they must be in different scope.

C Program to demonstrate the behaviour of Local variable and Global variable

#include <stdio.h>

// Global variable
int globalVariable = 10;
int main()
{
   // This variable can't be accessed in other functions
  int localVariable = 80;
  printf("I am Global Variable %d \n",globalVariable);
  printf("I am Local Variable %d ",localVariable);

    return 0;
}