Unterricht stunde 28.10

Reviewed-on: https://gitty.informatik.th-mannheim.de/3010261/pr3-ws202627/pulls/5

.devcontainer/devcontainer-lock.json

@@ -0,0 +1,9 @@
+{
+  "features": {
+    "ghcr.io/devcontainers/features/docker-in-docker:2": {
+      "version": "2.17.0",
+      "resolved": "ghcr.io/devcontainers/features/docker-in-docker@sha256:25b9f05705ffba7dbe503230ac76081419306f8c8bc88e0ce78c4ecd99a0c78c",
+      "integrity": "sha256:25b9f05705ffba7dbe503230ac76081419306f8c8bc88e0ce78c4ecd99a0c78c"
+    }
+  }
+}

.devcontainer/devcontainer.json

@@ -0,0 +1,26 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/docker-in-docker
+{
+	"name": "Docker in Docker",
+	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	"image": "mcr.microsoft.com/devcontainers/base:bookworm",
+
+	"features": {
+		"ghcr.io/devcontainers/features/docker-in-docker:2": {
+			"version": "latest",
+			"moby": "true"
+		}
+	}
+
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	// "forwardPorts": [],
+
+	// Use 'postCreateCommand' to run commands after the container is created.
+	// "postCreateCommand": "docker --version",
+
+	// Configure tool-specific properties.
+	// "customizations": {},
+
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}

.github/dependabot.yml

@@ -0,0 +1,12 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for more information:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+# https://containers.dev/guide/dependabot
+
+version: 2
+updates:
+ - package-ecosystem: "devcontainers"
+   directory: "/"
+   schedule:
+     interval: weekly

go/.devcontainer/Dockerfile

@@ -1,7 +1,7 @@
 FROM golang:1.27-bookworm
 
 RUN apt-get update \
-    && apt-get install -y build-essential \
+    && apt-get install -y build-essential ripgrep \
     && rm -rf /var/lib/apt/lists/*
 
 RUN apt-get update \

go/.devcontainer/devcontainer.json

@@ -5,11 +5,16 @@
     },
     "postCreateCommand": "go install github.com/go-delve/delve/cmd/dlv@latest && go install github.com/cweill/gotests/gotests@v1.9.0 && go install golang.org/x/tools/gopls@latest && go install golang.org/x/tools/cmd/goimports@latest && go install honnef.co/go/tools/cmd/staticcheck@latest",
     "customizations": {
-        "vscode": { "extensions": [
+        "vscode": {
+            "extensions": [
                 "golang.go",
                 "gruntfuggly.todo-tree",
                 "-github.copilot"
-        ]}
+            ],
+            "settings": {
+                "todo-tree.ripgrep.ripgrep": "/usr/bin/rg"
+            }
+        }
     },
     "remoteUser": "developer",
     "updateRemoteUserUID": true

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/11-functions.go

@@ -14,6 +14,11 @@ func plus(a int, b int) int {
 // 	return a + b
 // }
 
+func plus2(a int, b int) (result int) {
+	result = a + b
+	return
+}
+
 // A function with multiple parameters of the same type can be shortened by listing the type only once.
 func plusPlus(a, b, c int) int {
 	return a + b + c
@@ -26,6 +31,10 @@ func plusNamed(a, b int) (result int) {
 	return
 }
 
+func nonplusultra(a int, b int) (result int, description string) {
+	return a + b, fmt.Sprintf("the sum of %d and %d is %d, a, b, a+b")
+}
+
 // A function can return multiple values. Here we return the sum and a formatted string description of the operation.
 func plusDescription(a int, b int) (int, string) {
 	result := a + b
@@ -36,6 +45,7 @@ func main() {
 
 	res := plus(1, 2)
 	fmt.Println("1+2 =", res)
+	fmt.Println(plus(30, 18))
 
 	res = plusPlus(1, 2, 3)
 	fmt.Println("1+2+3 =", res)

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/calculatorEigen.go

@@ -0,0 +1,74 @@
+package main
+
+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
+
+	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 {
+
+			fmt.Print("Please enter a float: ")
+			fmt.Scan(&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")
+			}
+		}
+	}
+}

go/01-basics/go.mod

@@ -0,0 +1,3 @@
+module gitty.informatik.th-mannheim.de/steger/pr3-sose2026/go
+
+go 1.26.0

go/01-basics/maps.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+    "fmt"
+    "maps"
+)
+
+func main() {
+
+    m := make(map[string]int)
+
+    m["k1"] = 7
+    m["k2"] = 13
+
+    fmt.Println("map:", m)
+
+    v1 := m["k1"]
+    fmt.Println("v1:", v1)
+
+    v3 := m["k3"]
+    fmt.Println("v3:", v3)
+
+    fmt.Println("len:", len(m))
+
+    delete(m, "k2")
+    fmt.Println("map:", m)
+
+    clear(m)
+    fmt.Println("map:", m)
+
+    _, prs := m["k2"]
+    fmt.Println("prs:", prs)
+
+    n := map[string]int{"foo": 1, "bar": 2}
+    fmt.Println("map:", n)
+
+    n2 := map[string]int{"foo": 1, "bar": 2}
+    if maps.Equal(n, n2) {
+        fmt.Println("n == n2")
+    }
+}

go/01-basics/slices.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+    "fmt"
+    "slices"
+)
+
+func main() {
+
+    var s []string
+    fmt.Println("uninit:", s, s == nil, len(s) == 0)
+
+    s = make([]string, 3)
+    fmt.Println("emp:", s, "len:", len(s), "cap:", cap(s))
+
+    s[0] = "a"
+    s[1] = "b"
+    s[2] = "c"
+    fmt.Println("set:", s)
+    fmt.Println("get:", s[2])
+
+    fmt.Println("len:", len(s))
+
+    s = append(s, "d")
+    s = append(s, "e", "f")
+    fmt.Println("apd:", s)
+
+    c := make([]string, len(s))
+    copy(c, s)
+    fmt.Println("cpy:", c)
+
+    l := s[2:5]
+    fmt.Println("sl1:", l)
+
+    l = s[:5]
+    fmt.Println("sl2:", l)
+
+    l = s[2:]
+    fmt.Println("sl3:", l)
+
+    t := []string{"g", "h", "i"}
+    fmt.Println("dcl:", t)
+
+    t2 := []string{"g", "h", "i"}
+    if slices.Equal(t, t2) {
+        fmt.Println("t == t2")
+    }
+
+    twoD := make([][]int, 3)
+    for i := range 3 {
+        innerLen := i + 1
+        twoD[i] = make([]int, innerLen)
+        for j := range innerLen {
+            twoD[i][j] = i + j
+        }
+    }
+    fmt.Println("2d: ", twoD)
+}

go/02-next-level/02-methoden.go

@@ -0,0 +1,23 @@
+package main
+
+import "fmt"
+
+type Counter struct {
+	value int
+}
+
+func (c Counter /** value reciever **/) toString() string {
+	return fmt.Sprintf("Counter Value: %d", c.value)
+}
+
+func (c *Counter /**Pointer reciever**/) Increment() {
+	fmt.Printf("Inside Increment: %p\n", c)
+	c.value = c.value + 1
+}
+
+func main() {
+	c := Counter{}
+	fmt.Println(c)
+	c.Increment()
+	fmt.Println(c)
+}

go/03-modules/go.mod

@@ -1,4 +1,4 @@
-module gitty.informatik.th-mannheim.de/steger/pr3-ws202627/go/03-modules
+module gitty.informatik.th-mannheim.de/3010261/pr3-ws202627/go/03-modules
 
 go 1.25.0
 

go/03-modules/myMath/math_test.go

@@ -3,7 +3,7 @@ package myMath_test
 import (
 	"testing"
 
-	"gitty.informatik.hs-mannheim.de/steger/pr3-code/go/03-modules/myMath"
+	"gitty.informatik.hs-mannheim.de/3010261/pr3-code/go/03-modules/myMath"
 )
 
 func TestAdd(t *testing.T) {

go/04-design-pattern/go.mod

@@ -0,0 +1,3 @@
+module gitty.informatik.th-mannheim.de/3010261/pr3-ws202627/go/04-design-pattern
+
+go 1.27.3

go/04-design-pattern/main.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"fmt"
+
+	"gitty.informatik.th-mannheim.de/3010261/pr3-ws202627/go/04-design-pattern/patterns"
+)
+
+func main() {
+	noodle, err := patterns.NewNoodleMaker().
+		Name("Spaghetti").
+		Type("Lang").
+		Length(25).
+		Girth(2).
+		Build()
+	if err != nil {
+		fmt.Println("Fehler:", err)
+		return
+	}
+	fmt.Printf("%+v\n", noodle)
+
+	standard, _ := patterns.NewNoodleMaker().Build()
+	fmt.Printf("%+v\n", standard)
+
+	_, err = patterns.NewNoodleMaker().Length(0).Build()
+	if err != nil {
+		fmt.Println("Erwarteter Fehler:", err)
+	}
+}

go/04-design-pattern/patterns/designpattern.go

@@ -0,0 +1,48 @@
+package patterns
+
+import (
+	"errors"
+)
+
+type Noodle struct {
+	Type   string
+	Name   string
+	Length int
+	Girth  int
+}
+
+type NoodleMaker struct {
+	noodle Noodle
+}
+
+func NewNoodleMaker() *NoodleMaker {
+	return &NoodleMaker{
+		noodle: Noodle{"Röhre", "Fusilli", 10, 5},
+	}
+}
+
+func (b *NoodleMaker) Length(l int) *NoodleMaker {
+	b.noodle.Length = l
+	return b
+}
+func (c *NoodleMaker) Girth(g int) *NoodleMaker {
+	c.noodle.Girth = g
+	return c
+}
+func (d *NoodleMaker) Name(n string) *NoodleMaker {
+	d.noodle.Name = n
+	return d
+}
+func (e *NoodleMaker) Type(t string) *NoodleMaker {
+	e.noodle.Type = t
+	return e
+}
+func (m *NoodleMaker) Build() (Noodle, error) {
+	if m.noodle.Length <= 0 {
+		return Noodle{}, errors.New("Länge muss größer als 0 sein")
+	}
+	if m.noodle.Girth <= 0 {
+		return Noodle{}, errors.New("Dicke muss größer als 0 sein")
+	}
+	return m.noodle, nil
+}

go/04-design-pattern/patterns/designpattern_test.go

@@ -0,0 +1,48 @@
+package patterns
+
+import (
+	"testing"
+)
+
+func TestNoodleMaker(t *testing.T) {
+	tests := []struct {
+		name    string
+		build   func() (Noodle, error)
+		want    Noodle
+		wantErr bool
+	}{
+		{
+			name:  "Defaults",
+			build: func() (Noodle, error) { return newNoodleMaker().Build() },
+			want:  Noodle{Type: "Röhre", Name: "Fusilli", Length: 10, Girth: 5},
+		},
+		{
+			name: "New Noodle",
+			build: func() (Noodle, error) {
+				return newNoodleMaker().Name("Spaghetti").Type("Lang").Length(25).Girth(2).Build()
+			},
+			want: Noodle{Type: "Lang", Name: "Spaghetti", Length: 25, Girth: 2},
+		},
+		{
+			name:    "Length 0",
+			build:   func() (Noodle, error) { return newNoodleMaker().Length(0).Build() },
+			wantErr: true,
+		},
+		{
+			name:    "Girth -1",
+			build:   func() (Noodle, error) { return newNoodleMaker().Girth(-1).Build() },
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := tt.build()
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("error = %v, wantErr %v", err, tt.wantErr)
+			}
+			if !tt.wantErr && got != tt.want {
+				t.Errorf("got %+v, want %+v", got, tt.want)
+			}
+		})
+	}
+}

go/05-concurrency/deadlock.go

@@ -1,17 +1,27 @@
 package main
 
+import (
+	"fmt"
+	"time"
+)
+
 func print(ci <-chan int) {
 	//TODO: implement
+	for value := range ci {
+		time.Sleep(100 * time.Millisecond)
+		fmt.Println(value)
+
+	}
 }
 
 func main() {
 
 	c := make(chan int)
-
+	done := make(chan bool)
+	go func() { print(c); done <- true; close(done) }()
 	c <- 1
 	c <- 2
 	c <- 3
 	close(c)
-
-	print(c)
+	<-done
 }

go/05-concurrency/mergeSort.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"math/rand"
 	"sort"
+	"sync"
 	"time"
 )
 
@@ -22,6 +23,54 @@ func mergeSortSequential(data []float64) {
 	copy(data, merge(left, right))
 }
 
+func mergeSortParallel(data []float64) {
+	if len(data) <= 1000 {
+		mergeSortSequential(data)
+		return
+	}
+
+	mid := len(data) / 2
+	left := data[:mid]
+	right := data[mid:]
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	go func() { mergeSortParallel(left); wg.Done() }()
+
+	go func() { mergeSortParallel(right); wg.Done() }()
+
+	wg.Wait()
+
+	copy(data, merge(left, right))
+}
+
+func mergeSortChannelsInternal(data []float64, sorted chan<- float64) {
+
+	if len(data) < 1000 {
+		sortedData := make([]float64, len(data))
+		copy(sortedData, data)
+		mergeSortSequential(sortedData)
+
+		for _, := 0; i < count; i++ {
+
+		}
+		close(sorted)
+	}
+}
+
+func mergeSortChannels(data []float64) {
+	sorted := make(chan float64)
+	go mergeSortChannelsInternal(data, sorted)
+	sortedData := make([]float64, len(data))
+	i := 0
+	for x := range sorted {
+		sortedData[i] = x
+		i++
+	}
+	copy(data, sortedData)
+}
+
 func merge(left, right []float64) []float64 {
 	result := make([]float64, 0, len(left)+len(right))
 	i, j := 0, 0
@@ -58,7 +107,8 @@ func main() {
 	//2. SORTING
 	start := time.Now()
 
-	mergeSortSequential(data)
+	//mergeSortSequential(data)
+	mergeSortParallel(data)
 
 	elapsed := time.Since(start)
 	fmt.Printf("MergeSort took %s\n", elapsed)

go/05-concurrency/select.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"math/rand"
 	"time"
 )
@@ -8,12 +9,33 @@ import (
 func main() {
 
 	ch1 := make(chan string)
+	ch2 := make(chan string)
 
 	go func() {
 		time.Sleep(time.Duration(rand.Intn(5)+1) * time.Second)
 		ch1 <- "Message from channel 1"
 	}()
 
-	msg1 := <-ch1
-	println("Received:", msg1)
+	go func() {
+		time.Sleep(time.Duration(rand.Intn(5)+1) * time.Second)
+		ch2 <- "Message from channel 2"
+	}()
+
+	count := 10
+	var channels []chan string
+	for i := range count {
+		ch := make(chan string)
+		channels = append(channels, ch)
+		go func() {
+			time.Sleep(time.Duration(rand.Intn(5)+1) * time.Second)
+			ch <- fmt.Sprintln("Message from Channel %d", i)
+		}()
+	}
+
+	fanIn := make(chan string, count)
+	for i := range count {
+		go func() { fanIn <- <-channels[i] }()
+	}
+	println("Recieved: ", <-fanIn)
+
 }