Defining Classes II - Absolute Java - page 342

the denominator, or both may contain a minus sign. Define methods for addition,
subtraction, multiplication, and division of objects of your class Rational . These
methods should be static methods that each have two parameters of type Rational
and return a value of type Rational . For example, Rational.add(r1, r2) will
return the result of adding the two rational numbers (two objects of the class
Rational, r1 and r2 ). Define accessor and mutator methods as well as the methods
equals and toString . You should include a method to normalize the sign of the
rational number so that the denominator is positive and the numerator is either
positive or negative. For example, after normalization, 4 >- 8 would be represented

the same as 4 8. Also write a test program to test your class.

- >

Hints : Two rational numbers a b and c d are equal if a d equals c b .

> > * *

Part Two: Add a second version of the methods for addition, subtraction, multi-
plication, and division. These methods should have the same names as the static
version but should use a calling object and a single argument. For example, this
version of the add method (for addition) has a calling object and one argument. So
r1.add(r2) returns the result of adding the rationals r1 and r2 . Note that your
class should have all these methods; for example, there should be two methods
named add .

Alternate Part Two: Add a second version of the methods for addition, subtraction,
multiplication, and division. These methods should have the same names as the
static version but should use a calling object and a single argument. The methods
should be void methods. The result is given as the changed value of the calling
object. For example, this version of the add method (for addition) has a calling
object and one argument. Therefore,

r1.add(r2);

changes the values of the instance variables of r1 so they represent the result of
adding r2 to the original version of r1 . Note that your class should have all these
methods; for example, there should be two methods named add .
(If you want to do both Part Two and Alternate Part Two, they must be two
classes. You cannot include the methods from both Part Two and Alternate Part
Two in a single class. Do you know why?)
7. Part One: Define a class for complex numbers. A complex number is a number of
the form

a + b*i

For our purposes, a and b are numbers of type double , and i is a number that
represents the quantity

1. Represent a complex number as two values of type
double . Name the instance variables real and imaginary . (The instance variable
for the number that is multiplied by i is the one called imaginary .) Call the class
Complex . Include a constructor with two parameters of type double that can be
used to set the instance variables of an object to any values. Also include a construc-
tor that has only a single parameter of type double ; call this parameter realPart

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