How do local variables differ from global variables?

Local variables and global variables differ primarily in their scope and accessibility:

1. Scope:

   • Local Variables: Defined within a specific function or block and can only be accessed within that function or block. They are not visible outside of their defined scope.
   • Global Variables: Defined outside of any function and can be accessed from anywhere in the code, including inside functions.

2. Lifetime:

   • Local Variables: Exist only for the duration of the function call. Once the function exits, the local variable is destroyed.
   • Global Variables: Exist for the entire duration of the program's execution. They remain in memory until the program terminates.

3. Usage:

   • Local Variables: Used for temporary storage of data that is only relevant within a specific function.
   • Global Variables: Used for data that needs to be shared across multiple functions or throughout the program.

Here’s an example in Python to illustrate the difference:

# Global variable
global_var = "I'm global"

def my_function():
    # Local variable
    local_var = "I'm local"
    print(local_var)  # Accessible here
    print(global_var)  # Accessible here

my_function()

print(global_var)  # Accessible here
# print(local_var)  # This would raise an error because local_var is not accessible here

In this example, global_var can be accessed both inside and outside my_function(), while local_var can only be accessed within my_function().