Projektdateien hinzufügen.

Papier2/Papier2.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

Papier2/Program.cs

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+namespace Papier2
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Papier a4 = new Papier(29.7, 21);
+            //a4.SetLength(293.3);
+            //a4.SetWight(212);
+            a4.PrintInfos();
+        }
+    }
+
+    class Papier
+    {
+        private double lengthInCm;
+        private double widthInCm;
+        public Papier(double l, double w)
+        {
+            lengthInCm = l;
+            widthInCm = w;
+        }
+        public double GetLengthInCm() { return lengthInCm; }
+        //public void setlength(double l) 
+        //{ 
+        //    if (lengthincm == 0 && 1 > 0) 
+        //    { lengthincm = l; } 
+        //}
+        public double GetWidthInCm() {  return widthInCm; }
+        //public void SetWight(double w)
+        //{
+        //    if (widthInCm == 0 && w > 0)
+        //    { widthInCm = w; }
+        //}
+        public double GetArea()
+        { return GetLengthInCm() * GetWidthInCm(); }
+        public void PrintInfos()
+        { 
+            Console.Write($"Das Papier mit der Länge {GetLengthInCm():F2} cm");
+            Console.Write($" und der Breite {GetWidthInCm():F2} cm");
+            Console.WriteLine($" hat eine Fläche von {GetArea()/10000:F2} Quadratmeter.");
+        }
+    }
+}