exercises/threading_example: add

extras/threading_example/threading_example.py

@@ -0,0 +1,33 @@
+"""
+This program adds
+"""
+
+import sys
+import threading
+
+def count(where, how_much):
+    for i in range(how_much):
+        # Execute where[i % len(where)] += 1, print what is hapenning
+        cell = i % len(where)
+        value = where[cell]
+        thread = threading.get_native_id()
+        end = '\r' if i < how_much - 1 else '\n'
+        print(f'{thread=} {cell=} {value=}→{value + 1}', end=end)
+        where[cell] = value + 1
+
+workers = int(sys.argv[1])
+how_much = int(sys.argv[2])
+
+counters = [0] * 3
+print(f'start: {counters=}')
+
+threads = [threading.Thread(target=count, args=(counters, how_much))
+           for _ in range(workers)]
+
+for t in threads:
+    t.start()
+for t in threads:
+    t.join()
+
+print(f'final: {counters=}')
+print(f'       {sum(counters)=}')