This assignment will give you an opportunity to practice C++ operator overloading best-practices (and other C++ best practices) in a reasonably simple context. You will need to implement a simple Rational class that represents rational numbers as numerator / denominator. The goal will be to implement most of the basic arithmetic operators, as well as the stream-output operator.
Your Rational class should be implemented in the files rational.h and rational.cpp. The class should also satisfy the following requirements:
Represent positive and negative rational numbers as two int values, numerator and denominator. The denominator should never be negative or zero; the numerator may be any whole number.
Support initialization of the forms Rational{} (initializes to 0/1), Rational{n} (initializes to n/1), and Rational{n, d} (initializes to n/d). If d is 0, throw a std::invalid_argument exception with a suitable error message. If d is negative, invert the sign of both n and d so that d is positive (for example, Rational(-3, -5) = 3/5).
Don't forget that functions can specify default arguments; that is a very easy way to implement this set of initialization call-patterns. Additionally, the one-argument call-pattern will allow the compiler to implicitly convert integers into Rational numbers.
Provide a member function num() that returns the numerator, and another member function denom() that returns the denominator.
Provide a member function reciprocal() that returns a Rational object containing the reciprocal of the number (but leaves the number itself unchanged). (This function should also throw if the reciprocal has a 0 for the denominator, but that will happen automatically if your constructor is implemented correctly.)
Provide a member function reduce() that reduces the rational number such that the greatest common divisor of the numerator and denominator is 1. Note that this function should mutate the Rational object that it is invoked on.
You may find it helpful to implement a gcd(a, b) helper function; if you do this, make sure to put it in the private section of your class.
Also, if the numerator is 0 and the denominator is not 1, your reduce() function should modify the number to 0/1.
Support addition, subtraction, multiplication and division with both the simple arithmetic and compound assignment operators.
All of these operations should generate a result that is fully reduced; for example, 2/5 + 6/10 = 1/1.
Recall that compound-assignment operators +=, -=, *= and /= are best to implement as member operator-overloads, and the simple arithmetic operators +, -, * and / are best to implement as non-member operator overloads.
Additionally, think about how you might reuse your work. For example, you might implement -= in terms of +=, and /= in terms of *= using the reciprocal() operation.
Support stream-output using the << operator. If the denominator is 1, only output the numerator; if the denominator is not 1, output "numerator/denominator".
Make sure to follow const-correctness guidelines and use const and references everywhere that is appropriate.
Comment your class thoroughly in the Doxygen style, including a class-level description, and a comment for every data-member and member-function. (Comments may be brief if the function's purpose is obvious, but you must still comment all of these things.)
You do not need to create a Doxyfile or run Doxygen this time, as long as you follow the Doxygen format properly.
Make sure to comment illegal arguments, and exceptions that may be thrown and the circumstances that would cause them to be thrown.
A test suite for your class is provided here; make sure to fix any test failures you encounter.
Now that you know how to use make to automate your build process, create a Makefile for your project that builds and tests your Rational code.
The all target should build the test binary, but not run it.
The test target should run the test binary.
The clean target should delete .o files and binaries. As always, make sure to back up your code before testing your clean target for the first time!
Make sure all files are compiled with the -Wall and -Werror arguments (these will go in your CXXFLAGS variable) so that any malformed but otherwise legal code is identified by the compiler.
Once you have completed the above tasks, submit your work through csman. Make sure to submit these files:
Makefilerational.hrational.cppYou do not need to submit the test code; we will test your program with a fresh copy of these files.
Please also complete and submit a feedback survey with your submission, telling us about your experience with this assignment. Doing so will help us to improve CS11 Intro C++ in the future.
Copyright © 2018 by California Institute of Technology. All rights reserved. Generated from cpp-lab5.md.