Complete the following assignments from the textbook:

• P9.12. The netbrat tester is here. Student files for this and the five following problems are here.
• P10.9. The netbrat tester is here.
• P11.9. (This refers to the Worked Example that you should review as well.) The netbrat tester is here.
• P11.17. The netbrat tester is here. Use this coin class and this main class.
• P13.8. The netbrat tester is here.
• P13.9. The netbrat tester is here.
• Find the mistakes in the following attempt to solve Homework 4A:

  public class Homework4A
  {
     public static int[] findLocations(String s, String t) 
     {   
        ArrayList<Integer> ans = new ArrayList<Integer>();
        findLocationsHelper(s, t, 0, ans);
  
        int[] pos = new int[ans.size()];
        for(int i = 0; i < ans.size(); i++) pos[i] = ans.get(i);
        return pos;
     }
  
     public static void findLocationsHelper(String s, String t, int start, ArrayList<Integer> ans) 
     {   
        if (start < s.length() - 1) 
        {
           int pos = s.indexOf(t, start);
  
           if (!ans.contains(pos)) 
              ans.add(s.indexOf(t,start));
           findLocationsHelper(s, t, start, ans);
           start++;
        }
     }
  }

  There is one obvious mistake, one subtle one. In a file problem7.txt, provide (a) a description of each mistake (b) for each mistake, a trace with an example of your choice that demonstrates the mistake (c) a description how to fix the mistakes (d) a trace of the run findLocationsHelper("mississippi", "i", 0, ans).

• In the solution of homework 4, trace through the call

  Puzzle p = new Puzzle("123","4X6","789");
  boolean b = p.isSolved();

  Write down the sequence of line numbers that are executed in the isSolved method.