massive: move a lot of things

25-functions-and-pointers/07-pointers-composites/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"
+	"strings"
+)
+
+func main() {
+	fmt.Println("••••• ARRAYS")
+	arrays()
+
+	fmt.Println("\n••••• SLICES")
+	slices()
+
+	fmt.Println("\n••••• MAPS")
+	maps()
+
+	fmt.Println("\n••••• STRUCTS")
+	structs()
+}
+
+// -----------------------------------------------------------------------------
+
+type house struct {
+	name  string
+	rooms int
+}
+
+func structs() {
+	myHouse := house{name: "My House", rooms: 5}
+
+	addRoom(myHouse)
+
+	// fmt.Printf("%+v\n", myHouse)
+	fmt.Printf("structs()     : %p %+v\n", &myHouse, myHouse)
+
+	addRoomPtr(&myHouse)
+	fmt.Printf("structs()     : %p %+v\n", &myHouse, myHouse)
+
+	fmt.Printf("&myHouse.name : %p\n", &myHouse.name)
+	fmt.Printf("&myHouse.rooms: %p\n", &myHouse.rooms)
+}
+
+func addRoom(h house) {
+	h.rooms++
+	fmt.Printf("addRoom()     : %p %+v\n", &h, h)
+}
+
+func addRoomPtr(h *house) {
+	// (*h).rooms++
+	h.rooms++
+	fmt.Printf("addRoomPtr()  : %p %+v\n", h, h)
+}
+
+// -----------------------------------------------------------------------------
+
+func maps() {
+	confused := map[string]int{"one": 2, "two": 1}
+
+	fix(confused)
+
+	fmt.Println(confused)
+
+	// &confused["one"]
+}
+
+func fix(m map[string]int) {
+	m["one"] = 1
+	m["two"] = 2
+	m["three"] = 3
+}
+
+// -----------------------------------------------------------------------------
+
+func slices() {
+	dirs := []string{"up", "down", "left", "right"}
+
+	up(dirs)
+	fmt.Printf("slices list   : %p %q\n", &dirs, dirs)
+
+	upPtr(&dirs)
+	fmt.Printf("slices list   : %p %q\n", &dirs, dirs)
+}
+
+func up(list []string) {
+	for i := range list {
+		list[i] = strings.ToUpper(list[i])
+		fmt.Printf("up.list[%d]    : %p\n", i, &list[i])
+	}
+	// *list = append(*list, "HEISEN BUG")
+	list = append(list, "HEISEN BUG")
+
+	fmt.Printf("up list       : %p %q\n", &list, list)
+}
+
+func upPtr(list *[]string) {
+	lv := *list
+
+	for i := range lv {
+		lv[i] = strings.ToUpper(lv[i])
+	}
+	*list = append(*list, "HEISEN BUG")
+
+	fmt.Printf("upPtr list    : %p %q\n", list, list)
+}
+
+// -----------------------------------------------------------------------------
+
+func arrays() {
+	nums := [...]int{1, 2, 3}
+
+	incr(nums)
+	fmt.Printf("arrays nums   : %p\n", &nums)
+	fmt.Println(nums)
+
+	incrByPtr(&nums)
+	fmt.Println(nums)
+}
+
+func incr(nums [3]int) {
+	fmt.Printf("incr nums     : %p\n", &nums)
+
+	for i := range nums {
+		nums[i]++
+		fmt.Printf("incr.nums[%d]  : %p\n", i, &nums[i])
+	}
+}
+
+func incrByPtr(nums *[3]int) {
+	for i := range nums {
+		nums[i]++
+		// (*nums)[i]++
+	}
+}