COMP 170    -    PROGRAM VIII  (Fraction Calculator)

Design, test, and run a project, FractionCalculator, which contains a class, Fraction,  that defines Fraction objects and several instance methods corresponding to Fraction arithmetic operations (addition, multiplication, division, reduction to lowest terms).  A static method to find the greatest common divisor of two non-negative integers should also reside inside the Fraction class.  (You may assume that the fractions are all non-negative numbers.)  You will also design a class (or client), FractionCalculator, containing the main method which asks the user for input and performs standard arithmetic operations upon the fractions, and then prints the results.
 

Sample dialogue:

Welcome to Antoine Roquentin's fraction calculator.

Choose from the following menu (type the character of your choice):
A:  to add two fractions.
M:  to multiply two fractions.
D:  to divide two fractions.
R:  to reduce a fraction to lowest terms.
X:  to terminate this session.
A
Type your first fraction (Numerator on first line;  Denominator on next line):
13
2
Type your second fraction:
2
3
Thank you.  The sum of 13/2 and 2/3 is 43/6.

Choose from the following menu (type the character of your choice):
A:  to add two fractions.
M:  to multiply two fractions.
D:  to divide two fractions.
R:  to reduce a fraction to lowest terms.
X:  to terminate this session.
R
Type your fraction (Numerator on first line;  Denominator on next line):
400
1200
Thank you. The reduced form of 400/1200 is 1/3.

Choose from the following menu (type the character of your choice):
A:  to add two fractions.
M:  to multiply two fractions.
D:  to divide two fractions.
R:  to reduce a fraction to lowest terms.
X:  to terminate this session.
M
Type your first fraction (Numerator on first line;  Denominator on next line):
8
27
Type your second fraction:
3
4
Thank you.  The product of 8/27 and 3/4 is 2/9.

Choose from the following menu (type the character of your choice):
A:  to add two fractions.
M:  to multiply two fractions.
D:  to divide two fractions.
R:  to reduce a fraction to lowest terms.
X:  to terminate this session.
X
Thank you for using the Fraction Calculator.  Type any character to end session.

Notes:

• A robust program will alert the user to possible division by 0.
• To design your greatest common factor instance method (for reducing a fraction to lowest terms), you may use the most naive method:  Namely, to find the GCD of 50 and 75, first check 50, then 49, 48, etc. until success is achieved at 25.  If you wish, you may use the (faster) recursive Euclidean Algorithm which will be discussed in class. This method should be defined as a static method, not an instance method, and should reside in the Fraction class.
• Always express your answer in lowest terms.  For example, it is not acceptable to write: The sum of 4/2 and 8/4 is 16/4.  Instead, write:  The sum of 4/2 and 8/4 is 4/1. (Notice that the user can input fractions that are NOT in reduced form, yet the calculator always expresses an answer in lowest terms.)  For extra credit you may wish to improve the appearance of output, so that 4/1 is written simply as 4.
• For additional extra credit, modify your Fraction class so that an object includes a "sign" (char type) and a numerator (int) and denominator (int).  Define a subtraction method in the Fraction class.

All of the following should be contained in a two-pocket folder with your name, "Comp 170", and "day"/"evening" designation  in large letters on the outside of the folder.

•  Turn in a diskette with the code for your FractionCalculator class in the file FractionCalculator.java and your Fraction class in the file Fraction.java.  (Do not save these files in a directory.)
•  A hard copy (print-out) of the source code for your program.  Include your name on the diskette. Always keep a back-up copy!

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