Can you explain the concept of variable scope in programming?

The scope of a variable is the part of the program where the variable is accessible for use.

In Python, there are several levels of scope:

• Local — variables declared inside a function are only accessible within that function.
• Enclosing — variables from outer (enclosing) functions are accessible within nested functions.
• Global — variables declared at the module level are accessible throughout the module.
• Built-in — names defined in Python's standard library.

Example:

def outer():
    x = 10  # enclosing
    def inner():
        print(x)  # access to enclosing
    inner()

outer()

If a variable is not found in the local scope, the search proceeds to enclosing, then global, and finally built-in scopes.

The keywords global and nonlocal allow modification of variables in the global and enclosing scopes, respectively.