# ch15/example3.py

import time
import threading
from multiprocessing import Pool

COUNT = 50000000

def countdown(n):
    while n > 0:
        n -= 1

if __name__ == '__main__':

    #######################################################################
    # Sequential

    start = time.time()
    countdown(COUNT)

    print('Sequential program finished.')
    print(f'Took {time.time() - start : .2f} seconds.')
    print()

    #######################################################################
    # Multithreading

    thread1 = threading.Thread(target=countdown, args=(COUNT // 2,))
    thread2 = threading.Thread(target=countdown, args=(COUNT // 2,))

    start = time.time()
    thread1.start()
    thread2.start()
    thread1.join()
    thread2.join()

    print('Multithreading program finished.')
    print(f'Took {time.time() - start : .2f} seconds.')
    print()

    #######################################################################
    # Multiprocessing

    pool = Pool(processes=2)
    start = time.time()
    pool.apply_async(countdown, args=(COUNT//2,))
    pool.apply_async(countdown, args=(COUNT//2,))
    pool.close()
    pool.join()

    print('Multiprocessing program finished.')
    print(f'Took {time.time() - start : .2f} seconds.')