Add mutex

mutex/mutex.go

@@ -0,0 +1,44 @@
+package mutex
+
+import (
+	"fmt"
+	"sync"
+	"time"
+)
+
+type container struct {
+	mu      sync.Mutex
+	counter map[string]int
+}
+
+func Mutex() {
+	var wg sync.WaitGroup
+	c := container{
+		counter: map[string]int{
+			"a": 0,
+			"b": 0,
+		},
+	}
+
+	increment := func(key string, times uint) {
+		c.mu.Lock()
+		defer c.mu.Unlock()
+
+		time.Sleep(200 * time.Millisecond)
+
+		for range times {
+			c.counter[key]++
+		}
+
+		wg.Done()
+	}
+
+	wg.Add(3)
+	go increment("a", 1000)
+	go increment("b", 1000)
+	go increment("a", 1000)
+
+	wg.Wait()
+
+	fmt.Printf("counter after all increment() calls: %v\n", c.counter)
+}