Add concurrency

concurrency/cmd/mutex/main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"fmt"
+	"sync"
+)
+
+func main() {
+	var balance int = 100
+	// var mu sync.Mutex
+
+	fmt.Println("Initial balance:", balance)
+
+	// Apply concurrent adjustments to the balance.
+	// The sum of these adjustments is 0.
+	// We should see no changes in balance at the end.
+	var adjustments = []int{
+		-8, -4, -2, 0, 2, 4, 8,
+		-8, -4, -2, 0, 2, 4, 8,
+		-8, -4, -2, 0, 2, 4, 8,
+		-8, -4, -2, 0, 2, 4, 8,
+		-8, -4, -2, 0, 2, 4, 8,
+		-8, -4, -2, 0, 2, 4, 8,
+	}
+
+	var wg sync.WaitGroup
+	wg.Add(len(adjustments))
+
+	for _, adjustment := range adjustments {
+		go func(adjustment int) {
+			defer wg.Done()
+
+			// mu.Lock()
+
+			balance += adjustment
+
+			// mu.Unlock()
+
+		}(adjustment)
+	}
+
+	wg.Wait()
+
+	fmt.Println("Final balance:", balance)
+}

concurrency/cmd/mutex/run.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+for (( ; ; )) do
+    go run ./main.go
+    printf "\n"
+    sleep 0.5
+done