python/global_variables.py

47 lines
1.7 KiB
Python

"""
This script demonstrates the use of global variables and the `global` keyword in Python functions.
Global Variables:
- `age`: An integer representing a person's age.
Functions:
- birthday_greet():
- First definition: Prints a birthday greeting using the global `age` variable, incremented by 1 (without modifying the global variable).
- Second definition: Uses the `global` keyword to modify the global `age` variable by incrementing it by 1, then prints a birthday greeting.
- birthday_greet_global():
- First definition: Prints a birthday greeting using the global `age` variable, incremented by 5 (without modifying the global variable).
- Second definition: Uses the `global` keyword to modify the global `age` variable by incrementing it by 5, then prints a birthday greeting.
Demonstrates:
- The difference between accessing and modifying global variables inside functions.
- The effect of the `global` keyword on variable scope and assignment.
"""
age = 24
def birthday_greet():
print(f"Happy B-Day! You are {age + 1}! (local message)")
birthday_greet() # Call the local function
print("Global message", age) # Print the global variable
def birthday_greet_global():
print(f"Happy B-Day! You are {age + 5}! (global message)")
birthday_greet_global() # Call the global function
age = 20
def birthday_greet():
global age # Added 'global' keyword
age += 1
print(f"Happy B-Day! You are {age}! (local message)")
birthday_greet()
print("Global message", age)
def birthday_greet_global():
global age # Added 'global' keyword
age += 5
print(f"Happy B-Day! You are {age}! (global message)")
birthday_greet_global() # Call the global function