Alla exempel på Prestanda

2026-03-12 10:33:09 +01:00
commit 607b4151cb
133 changed files with 4493 additions and 0 deletions
--- a/LINQ-loop/Program.cs
+++ b/LINQ-loop/Program.cs
@@ -0,0 +1,74 @@
+using System.Diagnostics;
+
+class Program {
+    static void Main() {
+        while (true) {
+            Console.WriteLine();
+            Console.WriteLine("=== Prestanda-LINQ/Loop-meny ===");
+            Console.WriteLine("1: Summa med LINQ");
+            Console.WriteLine("2: Summa med loop");
+            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 generera? ");
+
+            var data = CreateRandomList(n, maxValue: n);
+
+            var sw = Stopwatch.StartNew();
+            long result = 0;
+
+            switch (choice) {
+                case "1":
+                    result = SumWithLinq(data);
+                    break;
+                case "2":
+                    result = SumWithLoop(data);
+                    break;
+                default:
+                    Console.WriteLine("Ogiltigt val. Försök igen.");
+                    continue;
+            }
+
+            sw.Stop();
+
+            Console.WriteLine($"Resultat: {result}");
+            Console.WriteLine($"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 List<long> CreateRandomList(int n, int maxValue) {
+        var rnd = new Random();
+        var list = new List<long>(n);
+        for (int i = 0; i < n; i++)
+            list.Add(rnd.Next(-maxValue, maxValue));
+        return list;
+    }
+
+    static long SumWithLinq(IEnumerable<long> numbers) {
+        return numbers.Where(n => n > 0).Sum(n => (long)n * 2);
+    }
+
+    static long SumWithLoop(IEnumerable<long> numbers) {
+        long sum = 0;
+        foreach (var n in numbers) {
+            if (n > 0) sum += (long)n * 2;
+        }
+
+        return sum;
+    }
+}