Description
This week’s assignment will have you write a program that examines classes further and also introduces
constructors. Feel free to work in pairs and ask for help early.
This program will require you to write a class called Fraction that represents a rational number. The
class should represent a fraction internally with two private data members: a numerator and a
denominator (assume whole numbers only). The public interface of the class must provide the following:
• A default constructor that sets the numerator and denominator to 1
• A constructor that accepts two parameters: a numerator and a denominator for the new
Fraction instance. Your code must ensure that:
o The denominator is not zero (if it is, output an error and exit)
o The denominator is not negative (i.e., if the fraction is supposed to be negative, the
numerator should be negative; if the parameters are both negative, the constructor
should make the fraction positive)
• Two member functions, sumWith and multiplyWith, that perform addition and multiplication
of this Fraction instance and another Fraction instance (so, each will have a single
Fraction type parameter). The functions should not modify either Fraction instance;
instead, they should create and return a new instance. The resulting Fraction instance does
not need to be in reduced form (unless you’re doing the extra credit).
• A member function called print that outputs the fraction. It should accept a single ofstream
argument (by reference) and output the fraction details (without a newline). Here is an example
(where N is the numerator value and D is the denominator value):
N/D
• Extra credit: A member function called simplify that reduces the fraction to its lowest terms
(12/15 = 4/5). If you do this, you should add a call of your simplify function within the
parameterized constructor definition.
Your program will consist of three files:
• A header file named fraction.h
• An implementation file for the header file, named fraction.cpp
• A main program file named main.cpp
The main program, main.cpp, has been provided for you. You will use this file as-is, except for the
addition of your preamble. It is your task to create the header and implementation files and then write
the correct function prototypes and definitions to make the main work.
Submitting your work
CSCI 136 Supervised Programming Lab
Lab Assignment #9
Fall 2014 Page 2
Each of your source code files must have a preamble at the top (see the programming rules and
guidelines document in Blackboard for more on the preamble).
Make sure you are in the folder with your source code files (use the ls command) and then run the
following to create a zip archive of them:
$ mkdir lastname_firstname_lab09
$ cp lab09a.cpp lastname_firstname_lab09/lab09a.cpp
$ cp lab09b.cpp lastname_firstname_lab09/lab09b.cpp
$ zip –r lastname_firstname_lab09.zip lastname_firstname_lab09/
You’ll need to change lastname and firstname to your actual last and first names (use lowercase
letters) in the steps above. Once you have your zipfile, you can use that file as your submission for the
assignment in Blackboard.
If you are working in pairs, then you should have both of your names included as comments in the
source code file’s preamble (see the programming rules and guidelines document in Blackboard for
more on the preamble). Also, write both your names to the notes section in the submission form when
submitting to Blackboard.
Sample output
$ ./lab09
1/2 + 2/3 = 7/6
1/2 * 2/3 = 2/6
-1/2 + -2/6 = -10/12
-1/2 * -2/6 = 2/12
1/2 + -3/5 = -1/10
1/2 * -3/5 = -3/10
3/5 + 2/5 = 25/25
3/5 * 2/5 = 6/25
Sample output (with reduction)
$ ./lab09
1/2 + 2/3 = 7/6
1/2 * 2/3 = 1/3
-1/2 + -1/3 = -5/6
-1/2 * -1/3 = 1/6
1/2 + -3/5 = -1/10
1/2 * -3/5 = -3/10
3/5 + 2/5 = 1/1
3/5 * 2/5 = 6/25
