commit 8ff3d31f2701962671f7b6dba2a336bd23a73ea1
Author: PrismRealm <alan159753@gmail.com>
Date:   Sat Mar 23 17:45:05 2019 +0800

    Initial commit

diff --git a/.DS_Store b/.DS_Store
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index 0000000..25e194e
Binary files /dev/null and b/.DS_Store differ
diff --git a/Problem 4.16/main.py b/Problem 4.16/main.py
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+++ b/Problem 4.16/main.py	
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+#!/usr/bin/python
+import threading
+import sys
+
+average_result = None
+minimum_result = None
+maximum_result = None
+
+def calculate_average(numbers: list):
+    global average_result
+    average_result = sum(numbers) / len(numbers)
+
+def calculate_minimum(numbers: list):
+    global minimum_result
+    minimum_result = min(numbers)
+
+def calculate_maximum(numbers: list):
+    global maximum_result
+    maximum_result = max(numbers)
+
+def main() -> int:
+    if len(sys.argv) == 1:
+        print('Error: One or many integer arguments are necessary.')
+        return 1
+
+    # Converting digit strings into integers
+    numbers = None
+    try:
+        numbers = [int(digit) for digit in sys.argv[1:]]
+    except:
+        print('Error: Every argument must be an integer.')
+        return 1
+
+    # Creating threads
+    average_thread = threading.Thread(target=calculate_average, args=(numbers,))
+    minimum_thread = threading.Thread(target=calculate_minimum, args=(numbers,))
+    maximum_thread = threading.Thread(target=calculate_maximum, args=(numbers,))
+  
+    # Starting the threads
+    average_thread.start()
+    minimum_thread.start()
+    maximum_thread.start()
+
+    # Waiting for the threads
+    average_thread.join()
+    minimum_thread.join()
+    maximum_thread.join()
+  
+    # Printing the results
+    global average_result, minimum_result, maximum_result
+    print('The average value is %d' % average_result)
+    print('The minimum value is %d' % minimum_result)
+    print('The maximum value is %d' % maximum_result)
+    return 0
+
+if __name__ == '__main__':
+    exit(main())
diff --git a/README.md b/README.md
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+The 4th assignment of Operating System
+===
+
+The program of `Problem 4.16` is in the directory `Problem 4.16`.  
+
+---
+
+The program of `Problem 4.16` requires Python 3.5.2 or newer version to execute.
+To execute the program, please move to the directory and type `python main.py <arguments>` or `python3 main.py <arguments>` in your command line interface.