Chapter 9, Problem 9E

Explanation of Solution

Creating a class “RationalAssert.java”:

• Import required package.
• Define the class “RationalAssert”.
  • Declare the private variables “the_numerator”, and “the_denominator”.
  • Define parameterized constructor.
    • Assign “numerator” to “the_numerator”.
    • Assign “denominator” to “the_denominator”.
    • Create an assertion with the condition “assert the_denominator != 0”.
  • Give mutator methods to set numerator and denominator.
  • Give accessor methods to get the value of numerator and denominator.
  • Give function definition for “value ()”.
    • Return the value produced by “the_numerator / the_denominator”.
  • Given function “toString ()”.
    • Return the string “the_numerator / the_denominator”.
  • Define the “main ()” method.
    • Create an object for “Scanner” class.
    • Declare the variables “n”, and “d”.
    • Get the numerator and denominator from the user.
    • Call the constructor by passing “n”, and “d”.
    • Call the function “value”.
    • Call the function to get the numerator and denominator.
    • Print new line.

Program:

Rational.java:

import java.util.Scanner;

//Define a class

public class RationalAssert

{

    //Declare required variables

    private int the_numerator;

    private int the_denominator;

    //Parameterized constructor

    public RationalAssert(int numerator, int denominator)

    {

        //Assign the value of numerator

        the_numerator = numerator;

        //Assign the value of denominator

        the_denominator = denominator;

        //Declare an assertion

        assert the_denominator != 0;

    }

    //Function to set the value of numerator

    public void setNumerator(int numerator)

    {

        //Set the value

        the_numerator = numerator;

    }

    //Function to set the denominator

    public void setDenominator(int denominator)

    {

        //Declare an assertion

        assert the_denominator != 0;

        //Assign the value

        the_denominator = denominator;

    }

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