158 lines
2.9 KiB
Go
158 lines
2.9 KiB
Go
// For more tutorials: https://blog.learngoprogramming.com
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//
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// Copyright © 2018 Inanc Gumus
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// Learn Go Programming Course
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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//
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package main
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import (
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"bufio"
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"encoding/json"
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"fmt"
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"os"
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"strconv"
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"strings"
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)
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const data = `
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[
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{
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"id": 1,
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"name": "god of war",
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"genre": "action adventure",
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"price": 50
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},
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{
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"id": 2,
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"name": "x-com 2",
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"genre": "strategy",
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"price": 40
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},
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{
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"id": 3,
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"name": "minecraft",
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"genre": "sandbox",
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"price": 20
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}
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]`
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func main() {
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type item struct {
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id int
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name string
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price int
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}
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type game struct {
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item
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genre string
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}
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// ----------------------------------------------------------
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// DECODING SOLUTION:
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// encodable and decodable game type
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type jsonGame struct {
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ID int `json:"id"`
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Name string `json:"name"`
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Genre string `json:"genre"`
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Price int `json:"price"`
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}
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// load the initial data from json
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var decoded []jsonGame
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if err := json.Unmarshal([]byte(data), &decoded); err != nil {
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fmt.Println("Sorry, there is a problem:", err)
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return
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}
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// load the data into usual game values
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var games []game
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for _, dg := range decoded {
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games = append(games, game{item{dg.ID, dg.Name, dg.Price}, dg.Genre})
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}
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// ----------------------------------------------------------
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// index the games by id
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byID := make(map[int]game)
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for _, g := range games {
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byID[g.id] = g
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}
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fmt.Printf("Inanc's game store has %d games.\n", len(games))
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in := bufio.NewScanner(os.Stdin)
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for {
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fmt.Printf(`
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> list : lists all the games
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> id N : queries a game by id
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> save : exports the data to json and quits
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> quit : quits
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`)
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if !in.Scan() {
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break
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}
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fmt.Println()
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cmd := strings.Fields(in.Text())
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if len(cmd) == 0 {
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continue
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}
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switch cmd[0] {
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case "quit":
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fmt.Println("bye!")
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return
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case "list":
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for _, g := range games {
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fmt.Printf("#%d: %-15q %-20s $%d\n",
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g.id, g.name, "("+g.genre+")", g.price)
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}
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case "id":
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if len(cmd) != 2 {
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fmt.Println("wrong id")
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continue
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}
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id, err := strconv.Atoi(cmd[1])
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if err != nil {
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fmt.Println("wrong id")
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continue
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}
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g, ok := byID[id]
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if !ok {
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fmt.Println("sorry. i don't have the game")
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continue
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}
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fmt.Printf("#%d: %-15q %-20s $%d\n",
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g.id, g.name, "("+g.genre+")", g.price)
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case "save":
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// load the data into the encodable game values
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var encodable []jsonGame
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for _, g := range games {
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encodable = append(encodable,
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jsonGame{g.id, g.name, g.genre, g.price})
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}
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out, err := json.MarshalIndent(encodable, "", "\t")
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if err != nil {
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fmt.Println("Sorry:", err)
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continue
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}
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fmt.Println(string(out))
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return
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}
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}
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}
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