142 of 234 test passing

src/main/java/rocks/zipcode/io/quiz4/collections/ComparableTreeSet.java

@@ -9,6 +9,8 @@ import java.util.TreeSet;
  */
 public class ComparableTreeSet<_> extends TreeSet implements Comparable {
 
+    TreeSet thisTree = this;
+
     public ComparableTreeSet(_... arr) {
         addAll(Arrays.asList(arr));
     }
@@ -17,15 +19,18 @@ public class ComparableTreeSet<_> extends TreeSet implements Comparable {
 
     }
 
-    public Integer compareTo(ComparableTreeSet<_> o) {
-        if(this.first().equals(o.first())){
-            return 0;
-        }
-        return -1;
+    public int compareTo(ComparableTreeSet<_> o) {
+        return thisTree.first().toString().compareTo(o.first().toString());
     }
 
     public String toString(){
-        return null;
+        String output = "[";
+        for(Object i : thisTree){
+            output = output + i + ", ";
+        }
+
+        output = output.substring(0, output.length() - 2) + "]";
+        return output;
     }
 
     @Override

src/main/java/rocks/zipcode/io/quiz4/collections/ZipCodeWilmington.java

@@ -23,11 +23,17 @@ public class ZipCodeWilmington {
 
     public void lecture(double numberOfHours) {
         for(Student i : students){
-            i.learn(numberOfHours/students.size());
+            i.learn(numberOfHours);
         }
     }
 
     public Map<Student, Double> getStudyMap() {
-        return null;
+
+        Map<Student, Double> map = new HashMap<>();
+
+        for(Student i : students){
+            map.put(i, i.getTotalStudyTime());
+        }
+        return map;
     }
 }

src/main/java/rocks/zipcode/io/quiz4/fundamentals/StringEvaluator.java

@@ -7,16 +7,7 @@ import java.util.*;
  */
 public class StringEvaluator {
     public static String[] getAllPrefixes(String string) {
-
-        Set set = new TreeSet();
-
-        for(int i = 0; i < string.length(); i++){
-            for(int j = 0; j < string.length(); j++){
-                set.add(string.substring(i, j));
-            }
-        }
-
-        return (String[]) set.stream().toArray(String[]::new);
+        return null;
     }
 
     public static String[] getCommonPrefixes(String string1, String string2) {

src/main/java/rocks/zipcode/io/quiz4/objectorientation/Student.java

@@ -5,7 +5,7 @@ package rocks.zipcode.io.quiz4.objectorientation;
  */
 public class Student {
 
-    private Double totalStudyTime;
+    private Double totalStudyTime = 0.0;
     private Integer id;
 
     public Student() {
@@ -17,7 +17,7 @@ public class Student {
     }
 
     public void learn(Double amountOfHours) {
-        totalStudyTime =+ amountOfHours;
+        totalStudyTime = totalStudyTime + amountOfHours;
     }
 
     public Double getTotalStudyTime() {