add code to run the countDuplicateCharacters() method in the main() method

Author: dbc2201

.idea/workspace.xml

@@ -2,6 +2,8 @@
 
 public class Main {
     public static void main(String[] args) {
-        System.out.println("Hello world!");
+        DuplicateCharactersCounter counter = new DuplicateCharactersCounter();
+        var duplicateCharacters = counter.countDuplicateCharacters("abcdefghijklmnopqrstuvwxyz");
+        System.out.println(duplicateCharacters);
     }
 }

src/main/java/io/github/dbc/Main.java

@@ -6,7 +6,6 @@
 import org.junit.jupiter.api.Test;
 
 class DuplicateCharactersCounterTest {
-
     private DuplicateCharactersCounter counter;
 
     @BeforeEach