add: x-tba structs

x-tba/structs/01-basics-part-i/main.go

@@ -0,0 +1,65 @@
+// 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() {
+	/*
+		USING VARIABLES
+	*/
+
+	// var (
+	// 	name, lastname string
+	// 	age            int
+	// )
+	//
+	// name, lastname = "Pablo", "Picasso"
+	// age = 95
+	//
+	// name2, lastname2 := "Sigmund", "Freud"
+	// age2 := 83
+	//
+	// fmt.Println("Picasso:", name, lastname, age)
+	// fmt.Println("Freud  :", name2, lastname2, age2)
+
+	/*
+		USING STRUCT VARIABLES
+	*/
+
+	// // declare a struct variable
+	// var picasso struct {
+	// 	name, lastname string
+	// 	age            int
+	// }
+
+	// create a new struct type
+	type person struct {
+		name, lastname string
+		age            int
+	}
+
+	// short-declare struct variable without field names
+	// you cannot omit values when you initialize without field names
+	picasso := person{
+		name:     "Pablo",
+		lastname: "Picasso",
+		age:      95,
+	}
+
+	// short-declare struct variable with field names
+	// omitted fields will be zeroed
+	freud := person{
+		name:     "Sigmund",
+		lastname: "Freud",
+		age:      83,
+	}
+
+	fmt.Printf("Picasso: %#v\n\n", picasso)
+	fmt.Printf("Freud  : %#v\n\n", freud)
+}

x-tba/structs/02-basics-part-ii/main.go

@@ -0,0 +1,53 @@
+// 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() {
+	// create a new struct type
+	type person struct {
+		name, lastname string
+		age            int
+	}
+
+	picasso := person{"Pablo", "Picasso", 95}
+	freud := person{name: "Sigmund", lastname: "Freud", age: 83}
+
+	// picasso.age++
+	// picasso.name = "Master"
+
+	master := picasso
+	// var master person
+	// master.name = picasso.name
+	// master.lastname = picasso.lastname
+	// master.age = picasso.age
+
+	master = freud
+	master.name = "Master"
+	master.age++
+
+	for _, p := range []person{picasso, freud, master} {
+		if p == picasso {
+			// if p.name == picasso.name &&
+			// 	p.lastname == picasso.lastname &&
+			// 	p.age == picasso.age {
+
+			// p is a copy
+			p.name = "Raphael"
+
+			fmt.Printf("%s's age is %d\n", p.name, p.age)
+		}
+	}
+
+	// Picasso is still the same
+	fmt.Printf("\n%s's age is %d\n", picasso.name, picasso.age)
+
+	// type team struct{ scores []int }
+	// _ = team{} == team{}
+}

x-tba/structs/TODO.md

@@ -0,0 +1,20 @@
+[x] what?
+[x] why?
+[x] struct type
+[x] struct literal
+[x] anonymous structs
+[x] named structs
+[x] struct fields
+[x] compare and assign
+[x] printing
+[ ] embedding
+
+**LATER:**
+[ ] exporting struct and fields
+[ ] funcs: constructor pattern
+[ ] using anonymous structs when testing
+[ ] pointers:
+    [ ] struct tags {json encode/decode} - project?
+    [ ] structs and pointers - later
+    [ ] padding and memory layout - later
+[ ] empty struct (in channels section)

x-tba/structs/xxx-using-in-maps/main.go

@@ -0,0 +1,19 @@
+package main
+
+import "fmt"
+
+func main() {
+	type book struct {
+		name, isbn string
+	}
+
+	kafka := book{"Kafka's Revenge", "S-001"}
+	golden := book{"Stay Golden", "S-002"}
+
+	books := make(map[book]int, 2)
+	books[kafka] = 100
+	books[golden] = 50
+
+	fmt.Printf("%s sold %d times\n", kafka.name, books[kafka])
+	fmt.Printf("%s sold %d times\n", golden.name, books[golden])
+}

x-tba/structs/xxx-wizards/cmd/marshal/main.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"encoding/json"
+	"io/ioutil"
+
+	"github.com/inancgumus/learngo/x-tba/structs/xxx-json/wizards"
+)
+
+func main() {
+	wizards := []wizards.Wizard{
+		{Name: "Albert", Lastname: "Einstein", Nick: "emc2"},
+		{Name: "Isaac", Lastname: "Newton", Nick: "apple"},
+		{Name: "Stephen", Lastname: "Hawking", Nick: "blackhole"},
+		{Name: "Marie", Lastname: "Curie", Nick: "radium"},
+		{Name: "Charles", Lastname: "Darwin", Nick: "fittest"},
+	}
+
+	bytes, err := json.Marshal(wizards)
+	if err != nil {
+		panic(err)
+	}
+
+	ioutil.WriteFile("wizards.json", bytes, 0644)
+
+	//
+	// PREVIOUSLY
+	//
+
+	// names := [...][3]string{
+	// 	{"First Name", "Last Name", "Nickname"},
+	// 	{"Albert", "Einstein", "emc2"},
+	// 	{"Isaac", "Newton", "apple"},
+	// 	{"Stephen", "Hawking", "blackhole"},
+	// 	{"Marie", "Curie", "radium"},
+	// 	{"Charles", "Darwin", "fittest"},
+	// }
+
+	// for i := range names {
+	// 	n := names[i]
+	// 	fmt.Printf("%-15s %-15s %-15s\n", n[0], n[1], n[2])
+
+	// 	if i == 0 {
+	// 		fmt.Println(strings.Repeat("=", 50))
+	// 	}
+	// }
+}

x-tba/structs/xxx-wizards/cmd/marshal/wizards.json

@@ -0,0 +1 @@
+[{"Name":"Albert","nick":"emc2"},{"Name":"Isaac","nick":"apple"},{"Name":"Stephen","nick":"blackhole"},{"Name":"Marie","nick":"radium"},{"Name":"Charles","nick":"fittest"}]

x-tba/structs/xxx-wizards/cmd/unmarshal/main.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"strings"
+
+	"github.com/inancgumus/learngo/x-tba/structs/xxx-json/wizards"
+)
+
+func main() {
+	file, err := ioutil.ReadFile("../marshal/wizards.json")
+	if err != nil {
+		panic(err)
+	}
+
+	wizards := make([]wizards.Wizard, 10)
+	if json.Unmarshal(file, &wizards) != nil {
+		panic(err)
+	}
+
+	fmt.Printf("%-15s %-15s\n%s",
+		"Name", "Nick", strings.Repeat("=", 25))
+
+	for _, w := range wizards {
+		fmt.Printf("%-15s %-15s\n", w.Name, w.Nick)
+	}
+}

x-tba/structs/xxx-wizards/wizards.go

@@ -0,0 +1,9 @@
+package wizards
+
+// Wizard is one of the greatest of people
+type Wizard struct {
+	// name won't be marshalled (should be exported)
+	Name     string `json:name`
+	Lastname string `json:"-"`
+	Nick     string `json:"nick"`
+}

x-tba/xxx-project-domain-visits.1/log.txt

@@ -0,0 +1,8 @@
+learngoprogramming.com 10
+learngoprogramming.com 5
+learngoprogramming.com 10
+learngoprogramming.com 20
+golang.org 4
+golang.org 6
+golang.org 5
+golang.org 10

x-tba/xxx-project-domain-visits.1/main.go

@@ -0,0 +1,64 @@
+// 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 (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	var (
+		// use a comparable struct for the keys
+		visits = make(map[string]int)
+
+		domains    []string
+		dupDomains = make(map[string]bool)
+
+		line int
+	)
+
+	in := bufio.NewScanner(os.Stdin)
+	for in.Scan() {
+		line++
+
+		fields := strings.Fields(in.Text())
+		if len(fields) != 2 {
+			fmt.Printf("Wrong input: %v\n", fields)
+			return
+		}
+
+		domain, svisit := fields[0], fields[1]
+
+		dvisit, err := strconv.Atoi(svisit)
+		if err != nil {
+			fmt.Printf("Wrong input: %q (line #%d)\n", svisit, line)
+			return
+		}
+		visits[domain] += dvisit
+
+		// only add the domain once
+		if !dupDomains[domain] {
+			domains = append(domains, domain)
+			dupDomains[domain] = true
+		}
+	}
+
+	// print the summary grouped by domain
+	var total int
+	for _, d := range domains {
+		v := visits[d]
+		fmt.Printf("%-25s -> %d\n", d, v)
+		total += v
+	}
+
+	fmt.Printf("\n%-25s -> %d\n", "TOTAL", total)
+}

x-tba/xxx-project-domain-visits.2b/log.txt

@@ -0,0 +1,8 @@
+learngoprogramming.com turkey 10
+learngoprogramming.com turkey 5
+learngoprogramming.com usa 10
+learngoprogramming.com usa 20fds
+golang.org germany 4
+golang.org germany 6
+golang.org italy 5
+golang.org italy 10

x-tba/xxx-project-domain-visits.2b/main.go

@@ -0,0 +1,82 @@
+// 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 (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	type visit struct {
+		domain  string
+		country string
+	}
+
+	var (
+		// use a comparable struct for the keys
+		visits = make(map[visit]int)
+
+		domains, countries []string
+		dupDomains         = make(map[string]bool)
+		dupCountries       = make(map[string]bool)
+
+		line int
+	)
+
+	in := bufio.NewScanner(os.Stdin)
+	for in.Scan() {
+		line++
+
+		fields := strings.Fields(in.Text())
+		if len(fields) != 3 {
+			fmt.Printf("Wrong input: %v\n", fields)
+			return
+		}
+
+		v := visit{
+			domain:  fields[0],
+			country: fields[1],
+		}
+
+		// increase the visit counts per domain + country
+		fhits := fields[2]
+
+		hits, err := strconv.Atoi(fhits)
+		if err != nil {
+			fmt.Printf("Wrong input: %q (line #%d)\n", fhits, line)
+			return
+		}
+		visits[v] += hits
+
+		// only add the domain once
+		if !dupDomains[v.domain] {
+			domains = append(domains, v.domain)
+			dupDomains[v.domain] = true
+		}
+
+		// only add the country once
+		if !dupCountries[v.country] {
+			countries = append(countries, v.country)
+			dupCountries[v.country] = true
+		}
+	}
+
+	// print the summary grouped by domain
+	for _, d := range domains {
+		fmt.Println(d)
+
+		for _, c := range countries {
+			v := visit{domain: d, country: c}
+			fmt.Printf("\t%s %d\n", c, visits[v])
+		}
+	}
+}