From 1d3fdf9c4d330379701539bd7b71bd1d31942b66 Mon Sep 17 00:00:00 2001
From: Syndamia <kamen.d.mladenov@protonmail.com>
Date: Sat, 3 Jul 2021 14:02:17 +0300
Subject: Finished Go tutorial

---
 Go/tutorial.go | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 211 insertions(+), 2 deletions(-)

diff --git a/Go/tutorial.go b/Go/tutorial.go
index 8230d13..353fc82 100644
--- a/Go/tutorial.go
+++ b/Go/tutorial.go
@@ -4,14 +4,202 @@ package main
 import (
 	"bufio"
 	"fmt"
+	"math"
 	"os"
 	"strconv"
 )
 
 func main() {
-	arrays()
+	// variablesAndPrinting()
+	// input()
+	// conditionals()
+	// loops()
+	// arrays()
+	// functions()
+	// pointers()
+	// structs()
+	interfaces()
 }
 
+/* Intefaces */
+
+type shape interface {
+	area() float64
+}
+
+type circle struct {
+	radius float64
+}
+
+type rect struct {
+	width  float64
+	height float64
+}
+
+func (c circle) area() float64 {
+	return math.Pi * c.radius * c.radius
+}
+
+func (r rect) area() float64 {
+	return r.width * r.height
+}
+
+func interfaces() {
+	var sh shape = circle{5}
+	fmt.Println(sh.area())
+	sh = rect{3, 8}
+	fmt.Println(sh.area())
+}
+
+/* Structs */
+
+type Point struct {
+	x int
+	y int
+}
+
+type Circle struct {
+	radius float64
+	*Point // struct composition
+}
+
+type Person struct {
+	name string
+	age  int
+}
+
+func (p Person) getAge() int {
+	return p.age
+}
+
+func (p Person) setAgeBroken(newAge int) {
+	p.age = newAge
+}
+
+func (p *Person) setAgeWorking(newAge int) {
+	p.age = newAge
+}
+
+func structs() {
+	var p1 Point = Point{1, 2}
+	p1.x = 5
+	fmt.Println(p1.x, p1.y)
+
+	p2 := Point{
+		x: 19,
+	}
+	fmt.Println(p2.x, p2.y) // p2.y is type default
+
+	c1 := Circle{3.14, &Point{30, 40}}
+	fmt.Println(c1, c1.x, c1.y)
+
+	person1 := Person{"John", 29}
+	fmt.Println(person1.getAge())
+	person1.setAgeBroken(19)
+	fmt.Println(person1.age)
+	person1.setAgeWorking(19)
+	fmt.Println(person1.age)
+}
+
+/* Pointers */
+
+func pointers() {
+	x := 7
+	fmt.Println(&x)
+
+	var y *int = &x
+	fmt.Println(x, y)
+	*y = 10
+	fmt.Println(x, y)
+
+	changeValue := func(str *string) {
+		*str = "Changed value!"
+	}
+	str := "Test"
+	changeValue(&str)
+	fmt.Println(str)
+}
+
+/* Functions */
+
+func print(x string) {
+	fmt.Println(x)
+}
+
+func printMultiple(msg1 string, msg2 string) {
+	fmt.Println(msg1, msg2)
+}
+
+func printMultiple1(msg1, msg2 string, n1 int) {
+	fmt.Println(msg1, msg2, 5)
+}
+
+func sum(a, b int) int {
+	return a + b
+}
+
+func sumAndSub(a, b int) (int, int) {
+	return a + b, a - b
+}
+
+func sumAndSubAlt(a, b int) (z1 int, z2 int) {
+	// Can be simplified just to: z1, z2 = a+b, a-b
+	z1 = a + b
+	z2 = a - b
+	return
+}
+
+func sumAndSubAlt1(a, b int) (z1 int, z2 int) {
+	defer fmt.Println("function ended") // defer statements execute when a function finishes
+	z1, z2 = a+b, a-b
+	return
+}
+
+func functions() {
+	print("Hello World")
+	printMultiple("One", "Two")
+	printMultiple1("One", "Two", 5)
+	fmt.Println(sum(1, 2))
+	fmt.Println(sumAndSub(1, 2))
+	fmt.Println(sumAndSubAlt(1, 2))
+	fmt.Println(sumAndSubAlt1(1, 2))
+
+	test := func() {
+		fmt.Println("test variable")
+	}
+	test()
+
+	// Saves a function and execution of it, so it saves what the function returns if given
+	// the number 9
+	test1 := func(x int) int {
+		return x * 2
+	}(9)
+	fmt.Println(test1)
+
+	test3 := func(f func()) {
+		f()
+	}
+	test3(test)
+
+	func() {
+		fmt.Println("woah")
+	}()
+
+	returnFunc := func(id int) func(int) int {
+		switch id {
+		case 1:
+			return func(n int) int { return n * 2 }
+		case 2:
+			return func(n int) int { return n * 3 }
+		default:
+			return func(n int) int { return n * -1 }
+		}
+	}
+	fmt.Println(returnFunc(2)(5))
+}
+
+/* Arrays */
+
 func arrays() {
 	var arr [5]int // fills with default value
 	arr[2] = 5
@@ -45,8 +233,23 @@ func arrays() {
 	for _, elem := range bigarr { // equivalent to this C# code: foreach(var elem in bigarr)
 		fmt.Println(elem)
 	}
+
+	// Maps are the Go equivalent of C# Dictionaries
+	mp := map[string]int{
+		"apple":  1,
+		"pear":   2,
+		"orange": 9,
+	}
+	fmt.Println(mp)
+	fmt.Println(mp["orange"])
+	delete(mp, "orange")
+	fmt.Println(mp)
+	val, exists := mp["adf"] // If value exists at key, val is assigned to it and exists is true, otherwise val is default for type and exists is false
+	fmt.Println(exists, val)
 }
 
+/* Loops */
+
 func loops() {
 	i = 0
 	for i < 5 {
@@ -68,6 +271,8 @@ func loops() {
 	}
 }
 
+/* Conditionals */
+
 func conditionals() {
 	age := 21
 	if driving_age := 18; age < driving_age {
@@ -96,6 +301,8 @@ func conditionals() {
 	}
 }
 
+/* User input */
+
 func input() {
 	scanner := bufio.NewScanner(os.Stdin)
 
@@ -112,7 +319,9 @@ func input() {
 
 }
 
-var i int
+/* Variables and printing */
+
+var i int // global variable
 
 func variablesAndPrinting() {
 	var msg string
-- 
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