CECS 277
LAB ASSIGNMENT #6
Assigned date: 4/6
Due date: 4/13
30 points

1. [3 points] Implement a generic version of the binary search algorithm.

/**
A class for executing binary searches through an array.
*/
public class BinarySearcher
{
private int[] a;

/**
Constructs a BinarySearcher.
@param anArray a sorted array
*/
public BinarySearcher(int[] anArray)
{
a = anArray;
}

/**
Finds a value in a sorted array, using the binary
search algorithm.
@param v the value to search
@return the index at which the value occurs, or -1
if it does not occur in the array
*/
public int search(int v)
{
int low = 0;
int high = a.length - 1;
while (low <= high)
{
int mid = (low + high) / 2;
int diff = a[mid] - v;

if (diff == 0) // a[mid] == v
return mid;
else if (diff < 0) // a[mid] < v
low = mid + 1;
else
high = mid - 1;
}
return -1;
}
}

2. [10 points] Rewrite the problem 2 in the lab assignment 4 by implementing the following methods:

• public static printMenuAndGetChoice()
  
  
• /**
        Adds a student based on user input.  Prints an error if a student
        is added that already exists in the map.
        @param gradeMap the map to associate student object with a grade
        @param StudentMap the map to associate student id with a student
     */
  
  
• /**
        Removes a student from the map based on user input
        @param gradeMap the map to associate student object with a grade
        @param StudentMap the map to associate student id with a student
     */
  
  
• /**
  Modifies an entry based on user input.  Prints an error if an invalid student is modified
        @param gradeMap the map to associate student object with a grade
        @param StudentMap the map to associate student id with a student
     */
  
  
  
•    /**
        Prints the students and grades
        @param gradeMap the map to print
     */
  
  

3. [10 points] Make the Measurable interface below into a generic class. Provide a static method that returns the largest element of ArrayList<T> provided that the elements are instances of Measure<T>. Be sure to return the value of type T.

public interface Measurable

{ double getMeasure();

}

Test your program by running the following main method.

import java.util.ArrayList;

/**
This program demonstrates the Measurable class.
*/
public class MeasurableDemo
{
public static void main(String[] args)
{
ArrayList<MeasurableString> words = new ArrayList<MeasurableString>();
words.add(new MeasurableString("Mary"));
words.add(new MeasurableString("had"));
words.add(new MeasurableString("a"));
words.add(new MeasurableString("little"));
words.add(new MeasurableString("lamb"));
System.out.println("Largest word: " + Measurable.largest(words));
System.out.println("Expected: little");
}
}

4. [7 points] Turn the HashSet implementation of chapter 16 into a generic class. Use an array list instead of an array to store the buckets.
Here is the links to th files HashSet.java and HashSetDemo.java in the chapter 16.

GRADING

• Turn in hard copies of your source code for all classes.
• Be ready to demonstrate the result and answer some questions about the lab assignment.