A java question. Write a class ClassManager which manages an ArrayList of String

Question

A java question. Write a class ClassManager which manages an ArrayList of String names. ClassManager has an ArrayList of Strings containing the names of students in the classas an instance variable. The constructor initializes the instance variable with an empty ArrayList

Provide the following methods:

public void enroll(String name) adds a name to the list of studentsenroll

public void sort() sorts the list of names. Do not write your own sort. Use the one from the Collections class in the Java library

public double averageLength() gets the average length of the names

public String getNames() gets a String consisting of all the names separated by a space.

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Use the following file:

ClassManagerTester.java

Explanation / Answer

ClassManager.java

import java.util.ArrayList;
import java.util.Collections;

public class ClassManager {
ArrayList<String> names = new ArrayList<String>();
public void enroll(String name) {
   names.add(name);
}
public void sort() {
   Collections.sort(names);
}
public double averageLength() {
   if(names.size() == 0){
       return 0.0;
   }
   int sum = 0;
   for(String name: names){
       sum = sum + name.length();
   }
   return sum/(double)names.size();
}
public String getNames() {
   String s="";
   for(String name: names){
       s = s + name+", ";
   }
   if(s.length()>0){
       s = s.substring(0, s.length()-2);
   }
   return s;
}
}

Output:

Armand, Nick, Zane
Expected: Armand Nick Zane
Alex, Armand, Nick, Zane
Expected: Alex Armand Nick Zane
4.5
Expected: 4.5

Expected:
0.0
Expected: 0.0

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