Alla exempel på Prestanda

Sortering/Program.cs

@@ -0,0 +1,94 @@
+using System.Diagnostics;
+
+class Program {
+    static void Main() {
+        while (true) {
+            Console.WriteLine();
+            Console.WriteLine("=== Prestanda-Sorteringsmeny ===");
+            Console.WriteLine("1: Bubblesort (O(n^2))");
+            Console.WriteLine("2: Inbyggd snabb sortering (Array.Sort)");
+            Console.WriteLine("0: Avsluta");
+            Console.Write("Ditt val: ");
+
+            var choice = Console.ReadLine();
+            if (choice == "0") {
+                Console.WriteLine("Avslutar...");
+                break;
+            }
+
+            int n = ReadPositiveInt("Hur många tal vill du sortera? ");
+
+            int[] data = CreateRandomArray(n, maxValue: n * 10);
+            Console.WriteLine();
+            Console.WriteLine($"Osorterat: {Preview(data)}");
+
+            var copy = (int[])data.Clone();
+
+            var sw = Stopwatch.StartNew();
+            switch (choice) {
+                case "1":
+                    BubbleSort(copy);
+                    break;
+                case "2":
+                    FastSort(copy);
+                    break;
+                default:
+                    Console.WriteLine("Ogiltigt val. Försök igen.");
+                    continue;
+            }
+
+            sw.Stop();
+
+            Console.WriteLine($"Sorterad:  {Preview(copy)}");
+            Console.WriteLine($"Tid: {sw.ElapsedMilliseconds} ms för n = {n}");
+        }
+    }
+
+    static int ReadPositiveInt(string prompt) {
+        while (true) {
+            Console.Write(prompt);
+            if (int.TryParse(Console.ReadLine(), out int n) && n > 0)
+                return n;
+            Console.WriteLine("Ange ett heltal större än 0.");
+        }
+    }
+
+    static int[] CreateRandomArray(int n, int maxValue) {
+        var rnd = new Random();
+        var arr = new int[n];
+        for (int i = 0; i < n; i++)
+            arr[i] = rnd.Next(maxValue + 1);
+        return arr;
+    }
+
+    static string Preview(int[] arr, int head = 10, int tail = 10) {
+        if (arr.Length <= head + tail)
+            return string.Join(", ", arr);
+
+        var headPart = string.Join(", ", arr[..head]);
+        var tailPart = string.Join(", ", arr[^tail..]);
+        return $"{headPart}, … , {tailPart}";
+    }
+
+    public static void BubbleSort(int[] arr) {
+        int n = arr.Length;
+        bool swapped;
+        for (int pass = 0; pass < n - 1; pass++) {
+            swapped = false;
+            for (int i = 0; i < n - 1 - pass; i++) {
+                if (arr[i] > arr[i + 1]) {
+                    int tmp = arr[i];
+                    arr[i] = arr[i + 1];
+                    arr[i + 1] = tmp;
+                    swapped = true;
+                }
+            }
+
+            if (!swapped) break;
+        }
+    }
+
+    public static void FastSort(int[] arr) {
+        Array.Sort(arr);
+    }
+}