add: quiz and exercises to pointers

26-pointers/exercises/03-fix-the-crash/main.go

@@ -0,0 +1,32 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+// ---------------------------------------------------------
+// EXERCISE: Fix the crash
+//
+// EXPECTED OUTPUT
+//
+//   brand: apple
+// ---------------------------------------------------------
+
+package main
+
+import "fmt"
+
+type computer struct {
+	brand *string
+}
+
+func main() {
+	var c *computer
+	change(c, "apple")
+	fmt.Printf("brand: %s\n", c.brand)
+}
+
+func change(c *computer, brand string) {
+	(*c.brand) = brand
+}

26-pointers/exercises/03-fix-the-crash/solution/main.go

@@ -0,0 +1,24 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+type computer struct {
+	brand *string
+}
+
+func main() {
+	c := &computer{} // init with a value (before: c was nil)
+	change(c, "apple")
+	fmt.Printf("brand: %s\n", *c.brand) // print the pointed value
+}
+
+func change(c *computer, brand string) {
+	c.brand = &brand // set the brand's address
+}