15.13. NumberGroup - Part C¶

Part c. The MultipleGroups class represents a collection of NumberGroup objects and is a NumberGroup. The MultipleGroups class stores the number groups in the instance variable groupList (shown below), which is initialized in the constructor.

private ArrayList<NumberGroup> groupList;

Write the MultipleGroups method contains. The method takes an integer and returns true if and only if the integer is contained in one or more of the number groups in groupList.

For example, suppose multiple1 has been declared as an instance of MultipleGroups and consists of the three ranges created by the calls:

new Range(5, 8)
new Range(10, 12)
new Range(1, 6)

The following table shows the results of several calls to contains.

15.13.1. Try and Solve It¶

Write the method contains below in the class MultiGroups. (Note that the original AP Question involved a NumberGroup interface which has been replaced with inheritance here).

Write the method contains below in the class MultiGroups.

import java.util.ArrayList;

class NumberGroup
{
    public boolean contains(int num)
    {
        /* Implementation not shown */
        return true;
    }
}

class Range extends NumberGroup
{
    // copy in your Range class from the previous lesson here
}

public class MultiGroups extends NumberGroup
{

private ArrayList<NumberGroup> groupList;

public MultiGroups(Range r1, Range r2, Range r3)
    {
        groupList = new ArrayList<NumberGroup>();
        groupList.add(r1);
        groupList.add(r2);
        groupList.add(r3);
    }

/**
     * Returns true if at least one of the number groups in this multiple group
     * contains num; false otherwise
     */
    public boolean contains(int num)
    {
        // Write the MultiGroup contains method here

}

// Main method to test the class
    public static void main(String[] args)
    {
        MultiGroups multiple1 =
                new MultiGroups(
                        new Range(5, 8), new Range(10, 12), new Range(1, 6));
        System.out.println(
                "Multiple1 contains 2 (should be true)? " + multiple1.contains(2));
        System.out.println(
                "Multiple1 contains 9 (should be false)? "
                        + multiple1.contains(9));
        System.out.println(
                "Multiple1 contains 6 (should be true)? " + multiple1.contains(6));
    } // end of main
}

====
 import static org.junit.Assert.*;

import org.junit.*;

import java.io.*;

// import java.util.ArrayList;

public class RunestoneTests extends CodeTestHelper
 {
     public RunestoneTests()
     {
         super("MultiGroups");
         // CodeTestHelper.sort = true;
     }

@Test
     public void testMain1()
     {
         boolean passed = false;

String expect =
                 "Multiple1 contains 2 (should be true)? true\n"
                     + "Multiple1 contains 9 (should be false)? false\n"
                     + "Multiple1 contains 6 (should be true)? true";

String output = getMethodOutput("main");

passed = getResults(expect, output, "Checking for expected output from main");
         assertTrue(passed);
     }

@Test
     public void testMain2()
     {
         boolean passed = false;

MultiGroups multiple1 =
                 new MultiGroups(new Range(5, 8), new Range(10, 12), new Range(15, 20));

String expect = "false";
         String output = "" + multiple1.contains(0);

passed =
                 getResults(
                         expect,
                         output,
                         "Checking that MultiGroups with Range(5, 8), Range(10, 12), Range(15, 20)"
                             + " contains(0) should be false");
         assertTrue(passed);
     }

@Test
     public void testMain3()
     {
         boolean passed = false;

MultiGroups multiple1 =
                 new MultiGroups(new Range(5, 8), new Range(10, 12), new Range(15, 20));

String expect = "true";
         String output = "" + multiple1.contains(11);

passed =
                 getResults(
                         expect,
                         output,
                         "Checking that MultiGroups with Range(5, 8), Range(10, 12), Range(15, 20)"
                             + " contains(11) should be true");
         assertTrue(passed);
     }
 }

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