Add pointer and password app

go-demo-4/main.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+	a := [4]int{1, 2, 3, 4}
+	reverse(&a)
+	fmt.Println(a)
+
+	var n *int
+	fmt.Println(*n)
+}
+
+func reverse(arr *[4]int) {
+	for idx, val := range *arr {
+		(*arr)[len(arr)-1-idx] = val
+	}
+}