Homework 1: A Fraction Class

• Assigned: Wednesday, 30 August 2000
• Due: 5pm, Tuesday, 5 September 2000

Summary: For this assignment, you will write a Java class so as to familiarize yourself with the components and techniques for writing Java programs. You may not have learned all the information for this assignment by the time it was assigned, you will have learned it well in advance of the due date for the assignment.

Group work: You should each write your own classes. However, you may discuss the assignment with each other and help each other correct problems.

Turning it in: Leave your code in a publically readable directory, and email me the location of that directory. Here's some sample Unix code for setting up the directory.

% mkdir CS152.HW1
% mv Fraction.java CS152.HW1
% mv TestFraction.java CS152.HW1
% share CS152.HW1
% cs CS152.HW1
% share Fraction.java
% share TestFraction.java

Assignment

In class, we began to consider a simple Faction class that implements simple fractions, with a numerator and denominator. Finish writing the basic class (we may add more facilities in the next assignment). You need not do anything special with nonpositive denominators.

Your Fraction class should provide the following constructors

• Fraction() - create a new fraction with a reasonable default value.
• Fraction(int num,int denom) - create a new fraction with numerator num and denominator denom.
• Fraction(int val) - create a new fraction with value val (that is, numerator val and denominator 1).

Your Fraction class should provide the following methods

• void setValue(int num, int demon) - set the value of the fraction.
• void setValue(Fraction f) - set the value of the fraction.
• int getNumerator() - get the numerator.
• int getDenominator() - get the denominator.
• float toFloat() - convert the fraction to a floating point number.
• String toString() - convert the fraction to a string of the form num/denom.
• Fraction add(Fraction f) - add a fraction to the current fraction. This should not modify the value of the current fraction.
• Fraction multiply(Fraction f) - multiply the current fraction by another fraction. This should not modify the value of the current fraction.
• Fraction subtract(Fraction f) - subtract a fraction from the current fraction. This should not modify the value of the current fraction.
• Fraction divide(Fraction f) - divide the value of the current fraction by f. This should not modify the value of the current fraction.
• Fraction add(int i) - an an integer to the current fraction This should not modify the value of the current fraction.

Once you have completed your basic class, create a class, TestFraction that provides a main routine that appropriate tests your routines. Here are some things that you might test:

• What happens with compound operations, such as
  f.Add(g).multiply(h)?

Extra Credit

Be creative in your choice of additional facilities for the Fraction class.