add: func exercises

25-functions/exercises/refactor-to-funcs-1/main.go

@@ -0,0 +1,150 @@
+// 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: Refactor the game store to funcs - step #1
+//
+//  Remember the game store program from the structs exercises?
+//  Now, it's time to refactor it to funcs.
+//
+//  Create games.go file
+//
+//     1- Move the structs there
+//
+//     2- Add a func that creates and returns a game.
+//
+//        Name  : newGame
+//        Inputs: id, price, name and genre
+//        Output: game
+//
+//     3- Add a func that adds a `game` to `[]game` and returns `[]game`:
+//
+//        Name  : addGame
+//        Inputs: []game, game
+//        Output: []game
+//
+//     4- Add a func that uses newGame and addGame funcs to load up the game
+//        store:
+//
+//        Name  : load
+//        Inputs: none
+//        Output: []game
+//
+//     5- Add a func that indexes games by ID:
+//
+//        Name  : indexByID
+//        Inputs: []game
+//        Output: map[int]game
+//
+//     6- Add a func that prints the given game:
+//
+//        Name  : printGame
+//        Inputs: game
+//
+//
+//  Go back to main.go and change the existing code with
+//  the new funcs that you've created. There are hints
+//  inside the code.
+//
+// ---------------------------------------------------------
+
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	type item struct {
+		id    int
+		name  string
+		price int
+	}
+
+	type game struct {
+		item
+		genre string
+	}
+
+	// load()
+	games := []game{
+		{
+			item:  item{id: 1, name: "god of war", price: 50},
+			genre: "action adventure",
+		},
+		{item: item{id: 2, name: "x-com 2", price: 40}, genre: "strategy"},
+		{item: item{id: 3, name: "minecraft", price: 20}, genre: "sandbox"},
+	}
+
+	// indexByID()
+	byID := make(map[int]game)
+	for _, g := range games {
+		byID[g.id] = g
+	}
+
+	fmt.Printf("Inanc's game store has %d games.\n", len(games))
+
+	in := bufio.NewScanner(os.Stdin)
+	for {
+		fmt.Printf(`
+  > list   : lists all the games
+  > id N   : queries a game by id
+  > quit   : quits
+
+`)
+
+		if !in.Scan() {
+			break
+		}
+
+		fmt.Println()
+
+		cmd := strings.Fields(in.Text())
+		if len(cmd) == 0 {
+			continue
+		}
+
+		switch cmd[0] {
+		case "quit":
+			fmt.Println("bye!")
+			return
+
+		case "list":
+			for _, g := range games {
+				// printGame()
+				fmt.Printf("#%d: %-15q %-20s $%d\n",
+					g.id, g.name, "("+g.genre+")", g.price)
+			}
+
+		case "id":
+			if len(cmd) != 2 {
+				fmt.Println("wrong id")
+				continue
+			}
+
+			id, err := strconv.Atoi(cmd[1])
+			if err != nil {
+				fmt.Println("wrong id")
+				continue
+			}
+
+			g, ok := byID[id]
+			if !ok {
+				fmt.Println("sorry. i don't have the game")
+				continue
+			}
+
+			// printGame()
+			fmt.Printf("#%d: %-15q %-20s $%d\n",
+				g.id, g.name, "("+g.genre+")", g.price)
+		}
+	}
+}