Chapter 3, Problem 17RE

Explanation of Solution

Program code:

Filename: “Counter.class”

// CounterTester.java

/**

A class to test the Counter class.

*/

class Counter

{

    private int value;

    /**

    Gets the current value of this counter.

    */

    public int getValue()

    {

        //@return the current value

        return value;

    }

    //defining click() method

    public void click()

    {

        /**Advances the value of this counter by 1.*/

        value = value + 1;

    }

    //defining reset() method

    public void reset()

    {

        /*Resets the value of this counter to 0.*/

        value = 0;

    }

}

Unit test class for “counter” class:

Filename: “CounterTester.java”

public class CounterTester

{

    /**

    Tests the methods of the Counter class.

    @param args not used

    */

    public static void main(String[] args)

    {

        //creating object of “counter” class

        Counter tally = new Counter();

        //calling “getvalue()”

        int result = tally.getValue();

        //prompt the value of variable result

        System.out.println(result);

        //prompting a string

        System.out.println("Expected 0");

        //calling count() method

        tally.click();

        tally.click();

        tally.click();

        //calling getValue() method

        result = tally...