diff --git a/Prog3.iml b/Prog3.iml
index c90834f..fed7bbb 100644
--- a/Prog3.iml
+++ b/Prog3.iml
@@ -3,9 +3,12 @@
   <component name="NewModuleRootManager" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/Test" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="junit.jupiter" level="project" />
+    <orderEntry type="library" name="mockito.core" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/Test/TriangleCheckerTest.java b/Test/TriangleCheckerTest.java
new file mode 100644
index 0000000..29d5924
--- /dev/null
+++ b/Test/TriangleCheckerTest.java
@@ -0,0 +1,36 @@
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class TriangleCheckerTest {
+
+    @Test
+    void checkNone() {
+        assertEquals(TriangleChecker.TriangleType.NONE, TriangleChecker.checkTriangle(0, 0, 0));
+
+
+
+    }
+    @Test
+    void checkNormal() {
+        assertEquals(TriangleChecker.TriangleType.NORMAL, TriangleChecker.checkTriangle(1, 2, 3));
+
+
+
+    }
+
+    @Test
+    void checkISOSCELES() {
+        assertEquals(TriangleChecker.TriangleType.ISOSCELES, TriangleChecker.checkTriangle(1, 1, 2));
+
+
+
+    }
+    @Test
+    void checkEQUILATERAL() {
+        assertEquals(TriangleChecker.TriangleType.EQUILATERAL, TriangleChecker.checkTriangle(1, 1, 1));
+
+
+
+    }
+}
\ No newline at end of file
diff --git a/Test/praktikum01/ZahlenfilterTest.java b/Test/praktikum01/ZahlenfilterTest.java
new file mode 100644
index 0000000..c73ed99
--- /dev/null
+++ b/Test/praktikum01/ZahlenfilterTest.java
@@ -0,0 +1,27 @@
+package praktikum01;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class ZahlenfilterTest {
+
+    @Test
+    void filter() {
+    }
+
+    @Test
+    void checkDivisibleBy5() {
+        assertTrue(Zahlenfilter.checkDivisibleBy5(5));
+        assertFalse(Zahlenfilter.checkDivisibleBy5(6));
+    }
+
+    @Test
+    void checkEndsWith9() {
+
+    }
+
+    @Test
+    void checkSumDivisibleBy3() {
+    }
+}
\ No newline at end of file
diff --git a/src/TriangleChecker.java b/src/TriangleChecker.java
new file mode 100644
index 0000000..ecfe0da
--- /dev/null
+++ b/src/TriangleChecker.java
@@ -0,0 +1,67 @@
+import java.util.Scanner;
+
+public class TriangleChecker {
+  
+  public enum TriangleType {
+    NONE, 
+    NORMAL,
+    ISOSCELES,  // Gleichschenklig
+    EQUILATERAL // Gleichseitig
+  }
+
+
+  public static void main(String[] args) {
+    Scanner s = new Scanner(System.in);
+    System.out.println("Geben Sie die Seitenlängen ein.");
+    float a = enterFloat(s, "a: ");
+    float b = enterFloat(s, "b: ");
+    float c = enterFloat(s, "c: ");
+    s.close();
+    printAnalysis(a, b, c);
+  }
+
+  // Eingabe einer Seitenlänge
+  private static float enterFloat(Scanner s, String prompt) {
+    System.out.print(prompt);
+    return s.nextFloat();
+  }
+
+  // Ausgabe der ermittelten Dreiecksart
+  private static void printAnalysis(float a, float b, float c) {
+    TriangleType type = checkTriangle(a, b, c);
+    switch (type) {
+      case NONE:
+        System.out.println("Kein Dreieck");
+        break;        
+      case NORMAL:
+        System.out.println("Dreieck");
+        break;        
+      case ISOSCELES:
+        System.out.println("Gleichschenkliges Dreieck");
+        break;        
+      case EQUILATERAL:
+        System.out.println("Gleichseitiges Dreieck");
+        break;        
+    }
+  }
+
+  // Analyse der Dreiecksart
+  public static TriangleType checkTriangle(float a, float b, float c) {
+    if( a <= 0 || b <= 0 || c <= 0){
+      return TriangleType.NONE;
+    }
+
+    if ( a == b && b == c){
+      return TriangleType.EQUILATERAL;
+
+    }
+    if (a == b && c > 0 || c == b && a > 0 || c == a && b > 0){
+
+      return TriangleType.ISOSCELES;
+    }
+
+    return TriangleType.NORMAL;
+  }
+
+
+}
\ No newline at end of file
diff --git a/src/praktikum01/ErrorWriter.java b/src/praktikum01/ErrorWriter.java
new file mode 100644
index 0000000..ee8f49c
--- /dev/null
+++ b/src/praktikum01/ErrorWriter.java
@@ -0,0 +1,9 @@
+package praktikum01;
+
+public class ErrorWriter implements HelloWorldTest{
+    @Override
+    public void writeHelloWorld() {
+        System.err.println("HELLO WORLD");
+
+    }
+}
diff --git a/src/praktikum01/Executor.java b/src/praktikum01/Executor.java
new file mode 100644
index 0000000..51c8e7e
--- /dev/null
+++ b/src/praktikum01/Executor.java
@@ -0,0 +1,9 @@
+package praktikum01;
+
+public class Executor implements HelloWorldTest{
+
+    @Override
+    public void printHelloWorld() {
+
+    }
+}
diff --git a/src/praktikum01/HelloWorldTest.java b/src/praktikum01/HelloWorldTest.java
new file mode 100644
index 0000000..cd093dc
--- /dev/null
+++ b/src/praktikum01/HelloWorldTest.java
@@ -0,0 +1,8 @@
+package praktikum01;
+
+public interface HelloWorldTest {
+    void writeHelloWorld();
+
+}
+
+
diff --git a/src/praktikum01/OutWriter.java b/src/praktikum01/OutWriter.java
new file mode 100644
index 0000000..6041702
--- /dev/null
+++ b/src/praktikum01/OutWriter.java
@@ -0,0 +1,9 @@
+package praktikum01;
+
+public class OutWriter implements HelloWorldTest{
+    @Override
+    public void writeHelloWorld() {
+        System.out.println("HELLO WORLD");
+
+    }
+}
diff --git a/src/praktikum01/PasswordChecker.java b/src/praktikum01/PasswordChecker.java
new file mode 100644
index 0000000..a2ff6c0
--- /dev/null
+++ b/src/praktikum01/PasswordChecker.java
@@ -0,0 +1,4 @@
+package praktikum01;
+
+public interface PasswordChecker {
+}
diff --git a/src/praktikum01/Zahlenfilter.java b/src/praktikum01/Zahlenfilter.java
index e633826..5449281 100644
--- a/src/praktikum01/Zahlenfilter.java
+++ b/src/praktikum01/Zahlenfilter.java
@@ -1,45 +1,38 @@
 package praktikum01;
 
+
 public class Zahlenfilter {
+    int boundary = 5000;
+
+
+
     public static void main(String[] args) {
-        for (int i = 1; i < 200; i++) {
-            int vorgaenger = i-1;
-            int ergebnis = i+vorgaenger;
-
-            if(i % 5 == 0){
-                System.out.println(i + " ist durch 5 teilbar");
-
-                if(ergebnis % 3 == 0){
-
-
-                    System.out.println(i + " und "+ vorgaenger + " addiert ergeben " + ergebnis + " und " + ergebnis + " ist durch 3 teilbar");
-
-
-                }
-
+        Zahlenfilter zahlenfilter = new Zahlenfilter();
+        zahlenfilter.printNumbers();
 
+    }
+    private void printNumbers(){
+        for (int i=1; i<=boundary; i++){
+            if (filter(i)){
+                System.out.println(i);
             }
-
-            if(i % 10 == 9){
-
-                System.out.println(i + " endet auf 9");
-
-                if(ergebnis % 3 == 0){
-
-
-                    System.out.println(i + " und "+ vorgaenger + " addiert ergeben " + ergebnis + " und " + ergebnis + " ist durch 3 teilbar");
-
-
-                }
-
-
-            }
-
-
-
-
-
         }
+    }
+
+    public static boolean filter(int i){
+        return !(checkDivisibleBy5(i) || checkEndsWith9(i) || checkSumDivisibleBy3(i, i-1));
+    }
+    public static boolean checkDivisibleBy5(int i){
+        return i % 2 == 0;
+    }
+
+    public static boolean checkEndsWith9(int i){
+        return i % 10 == 9;
+    }
+
+    public static boolean checkSumDivisibleBy3(int i, int j){
+        return i + j % 3 == 0;
 
     }
 }
+