Basics done

Author: Konsti-dev

10_pointers/main.go

@@ -0,0 +1,22 @@
+package main
+
+import "fmt"
+
+func main() {
+	a := 5
+	b := &a
+
+	fmt.Println(a, b)
+
+	fmt.Printf("%T\n", b)
+
+	// Use * to read val from address
+
+	fmt.Println(*b)
+	fmt.Println(*&a)
+
+	// Change val with pointer
+
+	*b = 10
+	fmt.Println(a)
+}

11_closures/main.go

@@ -0,0 +1,18 @@
+package main
+
+import "fmt"
+
+func adder() func(int) int {
+	sum := 0
+	return func(x int) int {
+		sum += x
+		return sum
+	}
+}
+
+func main() {
+	sum := adder()
+	for i := 0; i < 10; i++ {
+		fmt.Println(sum(i))
+	}
+}

12_structs/main.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+)
+
+// Define person struct
+
+type Person struct {
+	firstName, lastName, city, gender string
+	age                               int
+}
+
+// Greeting method (value reciever)
+func (p Person) greet() string {
+	return "Hell, my name is " + p.firstName + " " + p.lastName + " and I am " + strconv.Itoa(p.age)
+}
+
+// hasBirthday method (pointer reciever)
+func (p *Person) hasBirthday() {
+	p.age++
+}
+
+// getMarried (pointer reciever)
+func (p *Person) getMarried(spouseLastName string) {
+	if p.gender == "Männlich" {
+		return
+	} else {
+		p.lastName = spouseLastName
+	}
+}
+
+func main() {
+	// Init person using struct
+
+	/* person1 := Person{firstName: "Konstantin", lastName: "Komendantov", city: "Heilbronn", gender: "Männlich", age: 21} */
+	person2 := Person{"Konstantin", "Komendantov", "Neckarsulm-Amorbach", "Männlich", 21}
+	person3 := Person{"Susanne", "Schmidt", "Neckarsulm-Amorbach", "Weiblich", 21}
+
+	/* fmt.Println(person2)
+
+	fmt.Println(person2.firstName)
+	person2.age++
+	fmt.Println(person2) */
+
+	person2.hasBirthday()
+	fmt.Println(person2.greet())
+	person3.getMarried("Frank")
+	fmt.Println(person3.greet())
+
+}

13_interfaces/main.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+// Define interface
+type Shape interface {
+	area() float64
+}
+
+type Circle struct {
+	x, y, radius float64
+}
+
+type Rectangle struct {
+	width, height float64
+}
+
+func (c Circle) area() float64 {
+	return math.Pi * c.radius * c.radius
+}
+
+func (r Rectangle) area() float64 {
+	return r.width * r.height
+}
+
+func getArea(s Shape) float64 {
+	return s.area()
+}
+
+func main() {
+	circle := Circle{x: 0, y: 0, radius: 5}
+	rectangle := Rectangle{width: 10, height: 5}
+
+	fmt.Printf("Circle Area: %f\n", getArea(circle))
+	fmt.Printf("Circle Area: %f\n", getArea(rectangle))
+}

14_web/main.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+)
+
+func index(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "<h1>Hello World</h1>")
+}
+
+func about(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "<h1>Konsti-Dev</h1>")
+}
+
+func main() {
+	http.HandleFunc("/", index)
+	http.HandleFunc("/about", about)
+	fmt.Println("server Starting...")
+	http.ListenAndServe(":3000", nil)
+}