add: x-tba/foundations

x-tba/foundations/01-print-args/01-printf/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() {
+	var (
+		planet   = "venus"
+		distance = 261
+		orbital  = 224.701
+		hasLife  = false
+	)
+
+	// swiss army knife %v verb
+	fmt.Printf("Planet: %v\n", planet)
+	fmt.Printf("Distance: %v millions kms\n", distance)
+	fmt.Printf("Orbital Period: %v days\n", orbital)
+	fmt.Printf("Does %v have life? %v\n", planet, hasLife)
+
+	// argument indexing - indexes start from 1
+	fmt.Printf(
+		"%v is %v away. Think! %[2]v kms! %[1]v OMG.\n",
+		planet, distance,
+	)
+
+	// why use other verbs than? because: type-safety
+	// uncomment to see the warnings:
+	//
+	// fmt.Printf("Planet: %d\n", planet)
+	// fmt.Printf("Distance: %s millions kms\n", distance)
+	// fmt.Printf("Orbital Period: %t days\n", orbital)
+	// fmt.Printf("Does %v has life? %f\n", planet, hasLife)
+
+	// correct verbs:
+	// fmt.Printf("Planet: %s\n", planet)
+	// fmt.Printf("Distance: %d millions kms\n", distance)
+	// fmt.Printf("Orbital Period: %f days\n", orbital)
+	// fmt.Printf("Does %s has life? %t\n", planet, hasLife)
+
+	// precision
+	fmt.Printf("Orbital Period: %f days\n", orbital)
+	fmt.Printf("Orbital Period: %.0f days\n", orbital)
+	fmt.Printf("Orbital Period: %.1f days\n", orbital)
+	fmt.Printf("Orbital Period: %.2f days\n", orbital)
+}

x-tba/foundations/01-print-args/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"
+	"os"
+)
+
+func main() {
+	fmt.Println("There are", len(os.Args)-1, "people !")
+	fmt.Println("Hello great", os.Args[1], "!")
+	fmt.Println("Hello great", os.Args[2], "!")
+	fmt.Println("Hello great", os.Args[3], "!")
+	fmt.Println("Hello great", os.Args[4], "!")
+	fmt.Println("Hello great", os.Args[5], "!")
+	fmt.Println("Nice to meet you all.")
+
+	path := `c:\program files\duper super\fun.txt
+c:\program files\really\funny.png`
+
+	fmt.Println(path)
+}

x-tba/foundations/02-variables/01-basics/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"
+	"os"
+)
+
+func main() {
+	// var (
+	// 	name string
+	// 	name2 string
+	// 	name3 string
+	// )
+
+	// var name, name2, name3 string
+	// name = os.Args[1]
+	// name2 = os.Args[2]
+	// name3 = os.Args[3]
+
+	// name := os.Args[1]
+	// name2 := os.Args[2]
+	// name3 := os.Args[3]
+
+	name, name2, name3 := os.Args[1], os.Args[2], os.Args[3]
+
+	fmt.Println("Hello great", name, "!")
+	fmt.Println("And hellooo to you magnificient", name2, "!")
+	fmt.Println("Welcome", name3, "!")
+
+	// changes the name, declares the age with 131
+	name, age := "bilbo baggins", 131 // unknown age!
+
+	fmt.Println("My name is", name)
+	fmt.Println("My age is", age)
+	fmt.Println("And, I love adventures!")
+}

x-tba/foundations/02-variables/02-short-discard/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"
+	"math"
+	"os"
+	"path"
+	"strconv"
+)
+
+func main() {
+	var radius, area float64
+
+	radius, _ = strconv.ParseFloat(os.Args[1], 64)
+
+	area = 4 * math.Pi * math.Pow(radius, 2)
+	// area := 4 * math.Pi * math.Pow(radius, 2)
+
+	fmt.Printf("radius: %g -> area: %.2f\n",
+		radius, area)
+
+	dir, _ := path.Split("secret/file.txt")
+	fmt.Println(dir)
+
+	color, color2 := "red", "blue"
+	color, color2 = color2, color
+	fmt.Println(color, color2)
+}

x-tba/foundations/02-variables/03-conversion/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() {
+	min := int8(127)
+	max := int16(1000)
+
+	fmt.Println(max + int16(min))
+
+	// EXPLANATION
+	//
+	// `int8(max)` destroys the information of max
+	// It reduces it to 127
+	// Which is the maximum value of int8
+	//
+	// Correct conversion is int16(min)
+	// Because, int16 > int8
+	// When you do so, min doesn't lose information
+	//
+	// You will learn more about this in
+	// the "Go Type System" section.
+}

x-tba/foundations/03-if-switch-loop/01-for-crunch-the-primes/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/
+//
+
+// go run . {1..100}
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+)
+
+func main() {
+	// remember [1:] skips the first argument
+
+main:
+	for _, arg := range os.Args[1:] {
+		n, err := strconv.Atoi(arg)
+		if err != nil {
+			// skip non-numerics
+			continue
+		}
+
+		switch {
+		// prime
+		case n == 2 || n == 3:
+			fmt.Print(n, " ")
+			continue
+
+		// not a prime
+		case n <= 1 || n%2 == 0 || n%3 == 0:
+			continue
+		}
+
+		for i, w := 5, 2; i*i <= n; {
+			// not a prime
+			if n%i == 0 {
+				continue main
+			}
+
+			i += w
+			w = 6 - w
+		}
+
+		// all checks ok: it's a prime
+		fmt.Print(n, " ")
+	}
+
+	fmt.Println()
+}

x-tba/foundations/03-if-switch-loop/02-switch-months/main.go

@@ -0,0 +1,44 @@
+// 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"
+	"os"
+	"strings"
+	"time"
+)
+
+func main() {
+	if len(os.Args) != 2 {
+		fmt.Println("Give me a month name")
+		return
+	}
+
+	year := time.Now().Year()
+	leap := year%4 == 0 && (year%100 != 0 || year%400 == 0)
+
+	days, month := 28, os.Args[1]
+
+	switch strings.ToLower(month) {
+	case "april", "june", "september", "november":
+		days = 30
+	case "january", "march", "may", "july",
+		"august", "october", "december":
+		days = 31
+	case "february":
+		if leap {
+			days = 29
+		}
+	default:
+		fmt.Printf("%q is not a month.\n", month)
+		return
+	}
+
+	fmt.Printf("%q has %d days.\n", month, days)
+}

x-tba/foundations/03-if-switch-loop/03-math-table-if-switch-loop/main.go

@@ -0,0 +1,85 @@
+// 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"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const (
+	validOps = "%*/+-"
+
+	usageMsg       = "Usage: [op=" + validOps + "] [size]"
+	sizeMissingMsg = "Size is missing"
+	invalidOpMsg   = `Invalid operator.
+Valid ops one of: ` + validOps
+
+	invalidOp = -1
+)
+
+func main() {
+	args := os.Args[1:]
+
+	switch l := len(args); {
+	case l == 1:
+		fmt.Println(sizeMissingMsg)
+		fallthrough
+	case l < 1:
+		fmt.Println(usageMsg)
+		return
+	}
+
+	op := args[0]
+	if strings.IndexAny(op, validOps) == invalidOp {
+		fmt.Println(invalidOpMsg)
+		return
+	}
+
+	size, err := strconv.Atoi(args[1])
+	if err != nil || size <= 0 {
+		fmt.Println("Wrong size")
+		return
+	}
+
+	fmt.Printf("%5s", op)
+	for i := 0; i <= size; i++ {
+		fmt.Printf("%5d", i)
+	}
+	fmt.Println()
+
+	for i := 0; i <= size; i++ {
+		fmt.Printf("%5d", i)
+
+		for j := 0; j <= size; j++ {
+			var res int
+
+			switch op {
+			case "*":
+				res = i * j
+			case "%":
+				if j != 0 {
+					res = i % j
+				}
+			case "/":
+				if j != 0 {
+					res = i / j
+				}
+			case "+":
+				res = i + j
+			case "-":
+				res = i - j
+			}
+
+			fmt.Printf("%5d", res)
+		}
+		fmt.Println()
+	}
+}

x-tba/foundations/03-if-switch-loop/04-lucky-number-if-for-switch/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"
+	"math/rand"
+	"os"
+	"strconv"
+	"time"
+)
+
+const (
+	maxTurns = 5 // less is more difficult
+	usage    = `Welcome to the Lucky Number Game! 🍀
+
+The program will pick %d random numbers.
+Your mission is to guess one of those numbers.
+
+The greater your number is, harder it gets.
+
+Wanna play?
+
+(Provide -v flag to see the picked numbers.)
+`
+)
+
+func main() {
+	rand.Seed(time.Now().UnixNano())
+
+	args := os.Args[1:]
+	if len(args) != 1 {
+		fmt.Printf(usage, maxTurns)
+		return
+	}
+
+	var verbose bool
+	if args[0] == "-v" {
+		verbose = true
+	}
+
+	guess, err := strconv.Atoi(args[0])
+	if err != nil {
+		fmt.Println("Not a number.")
+		return
+	}
+
+	if guess < 0 {
+		fmt.Println("Please pick a positive number.")
+		return
+	}
+
+	for turn := 0; turn < maxTurns; turn++ {
+		n := rand.Intn(guess + 1)
+
+		if verbose {
+			fmt.Printf("%d ", n)
+		}
+
+		if n == guess {
+			switch rand.Intn(3) {
+			case 0:
+				fmt.Println("🎉  YOU WIN!")
+			case 1:
+				fmt.Println("🎉  YOU'RE AWESOME!")
+			case 2:
+				fmt.Println("🎉  PERFECT!")
+			}
+			return
+		}
+	}
+
+	msg := "%s Try again?\n"
+
+	switch rand.Intn(2) {
+	case 0:
+		fmt.Printf(msg, "☠️  YOU LOST...")
+	case 1:
+		fmt.Printf(msg, "☠️  JUST A BAD LUCK...")
+	}
+
+}

x-tba/foundations/03-if-switch-loop/05-path-searcher-for-range/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"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func main() {
+	// Get and split the PATH environment variable
+
+	// SplitList function automatically finds the
+	// separator for the path env variable
+	words := filepath.SplitList(os.Getenv("PATH"))
+
+	// Alternative way, but above one is better:
+	// words := strings.Split(
+	// 	os.Getenv("PATH"),
+	// 	string(os.PathListSeparator))
+
+	query := os.Args[1:]
+
+	for _, q := range query {
+		for i, w := range words {
+			q, w = strings.ToLower(q), strings.ToLower(w)
+
+			if strings.Contains(w, q) {
+				fmt.Printf("#%-2d: %q\n", i+1, w)
+			}
+		}
+	}
+}