Aufgaben bearbeitet

go/00-hello-world/hello-world.go

@@ -2,6 +2,11 @@ package main
 
 import "fmt"
 
-func main() {
-	fmt.Println("hello world")
+//go:fix inline
+func varOf(x int) *int {
+	return new(x)
+}
+
+func main() {
+	fmt.Println(new(10))
 }

go/01-basics/basics.go

@@ -0,0 +1,118 @@
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+const h string = "constant"
+
+// zeroval bekommt eine KOPIE: Änderung wirkt nur lokal.
+func zeroval(ival int) {
+	ival = 0
+}
+
+// zeroptr bekommt die ADRESSE: Änderung wirkt auf das Original.
+func zeroptr(iptr *int) {
+	*iptr = 0
+}
+
+func basics() {
+	fmt.Println("go", "lang")
+	fmt.Println("go" + "lang")
+	fmt.Println(7 / 3) // 2 (Ganzzahldivision)
+	fmt.Println(true || false)
+	fmt.Println(!true)
+}
+
+func variables() {
+	var a = "Initial" // Typ wird inferiert
+	fmt.Println(a)
+	a = "string"
+	fmt.Println(a)
+
+	var b int // Nullwert: 0
+	var c = 4
+	var x, y, z int = 1, 3, 6
+	fmt.Println(b, c)
+	fmt.Println(x, y, z)
+
+	s, z := "string", 8 // s neu, z nur neu zugewiesen
+	fmt.Println(s, z)
+
+	svar := h
+	fmt.Println(svar)
+}
+
+func constants() {
+	const n = 500000
+	const q = 3e20 / n // untypisiert, wird zur Compile-Zeit berechnet
+	fmt.Println(q)     // 6e+14
+	i := int64(n)
+	fmt.Println(math.Sin(float64(i)))
+	fmt.Println(math.Sin(n)) // untypisierte Konstante passt sich an
+}
+
+func controlFlow() {
+	// Schleife mit Abbruchbedingung
+	count := 0
+	for {
+		fmt.Println("hello")
+		count++
+		if count >= 3 {
+			break
+		}
+	}
+
+	j := 2
+	switch j {
+	case 1:
+		fmt.Println("one")
+	case 2, 3:
+		fmt.Println("two or three")
+	default:
+		fmt.Println("other")
+	}
+}
+
+func arrays() {
+	var u [5]int
+	u[2] = 4
+	v := [...]int{1, 3, 4, 5, 6, 3} // Länge wird vom Compiler gezählt
+	fmt.Println(u, v, len(v))
+}
+
+func pointers() {
+	t := 1
+	zeroval(t)
+	fmt.Println(t) // 1, unverändert
+	zeroptr(&t)
+	fmt.Println(t) // 0, verändert
+
+	j := 2
+	p := &j
+	fmt.Println(*p) // 2 (Dereferenzierung)
+}
+func slices() {
+	a := []int{}
+	a = append(a, 5, 6, 6, 9, 7, 8)
+	a = append(a, 6)
+	a = append(a, 7)
+	a[3] = 99
+	a = append(a, 8)
+	b := a
+	a = append(a, 9)
+	fmt.Println(a, len(a))
+	fmt.Println(b)
+
+}
+
+func main() {
+	basics()
+	variables()
+	constants()
+	controlFlow()
+	arrays()
+	pointers()
+	slices()
+}

go/01-basics/calculator.go

@@ -4,19 +4,71 @@ import (
 	"fmt"
 )
  
+const (
+	opAdd      = "add"
+	opSubtract = "subtract"
+	opMultiply = "multiply"
+	opDivide   = "divide"
+	opExit     = "exit"
+)
+ 
+var result float64
+ 
+func add(a, b float64) {
+	result = a + b
+}
+func multiply(a, b float64) {
+	result = a * b
+}
+func subtract(a, b float64) {
+	result = a - b
+}
+func divide(a, b float64) {
+	result = a / b
+}
+ 
 func main() {
+	var x float64
+	var y float64
 
 	//TODO: implement according to README.md 
 
 	//the following code just demonstrates how to use fmt.Scan
 
-	var str string
-	fmt.Print("Please enter a string: ")
-	fmt.Scan(&str)
+		for {
+		fmt.Print("What would you like to do? (add|subtract|divide|multiply|exit)")
+		var str string
+		fmt.Scan(&str)
+		if str == opExit {
+			break
+		} else {
  
-	var x float64
-	fmt.Print("Please enter a float: ")
-	fmt.Scan(&x)
+			fmt.Print("Please enter a float: ")
+			fmt.Scan(&x)
  
-	fmt.Printf("You entered '%s' and %f\n", str, x)
+			fmt.Print("Please enter a float: ")
+			fmt.Scan(&y)
+ 
+			switch str {
+			case opAdd:
+				add(x, y)
+				fmt.Println(result)
+			case opMultiply:
+				multiply(x, y)
+				fmt.Println(result)
+			case opDivide:
+				if y == 0 {
+					fmt.Println("Division by 0 is not possible")
+					continue
+				}
+				divide(x, y)
+				fmt.Println(result)
+			case opSubtract:
+				subtract(x, y)
+				fmt.Println(result)
+			default:
+				fmt.Println("Unknown operation")
+			}
+		}
+	}
 }