add: quiz and exercises to pointers

26-pointers/exercises/02-swap/main.go

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+// 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: Swap
+//
+//  Using funcs, swap values through pointers, and swap
+//  the addresses of the pointers.
+//
+//
+//  1- Swap the values through a func
+//
+//     a- Declare two float variables
+//
+//     b- Declare a func that can swap the variables' values
+//        through their memory addresses
+//
+//     c- Pass the variables' addresses to the func
+//
+//     d- Print the variables
+//
+//
+//  2- Swap the addresses of the float pointers through a func
+//
+//     a- Declare two float pointer variables and,
+//        assign them the addresses of float variables
+//
+//     b- Declare a func that can swap the addresses
+//        of two float pointers
+//
+//     c- Pass the pointer variables to the func
+//
+//     d- Print the addresses, and values that are
+//        pointed by the pointer variables
+//
+// ---------------------------------------------------------
+
+package main
+
+func main() {
+}

26-pointers/exercises/02-swap/solution/main.go

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+// 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"
+
+func main() {
+	a, b := 3.14, 6.28
+	swap(&a, &b)
+	fmt.Printf("a : %g — b : %g\n", a, b)
+
+	pa, pb := &a, &b
+	pa, pb = swapAddr(pa, pb)
+	fmt.Printf("pa: %p — pb: %p\n", pa, pb)
+	fmt.Printf("pa: %g — pb: %g\n", *pa, *pb)
+}
+
+func swap(a, b *float64) {
+	*a, *b = *b, *a
+}
+
+func swapAddr(a, b *float64) (*float64, *float64) {
+	return b, a
+}