In this class period we will code and test a class specification called Fraction that implements a rational number. A rational number is defined as the ratio of two integers, a numerator and denominator. The Fraction class can print itself in the form a/b. It can also give its value in decimal. Other operations that the Fraction can perform are:

• It can add another Fraction to itself.
• It can subtract another Fraction from itself.
• It can multiply another Fraction times itself.
• It can divide another Fraction by itself.

When reading the specification it is a good idea to work out some examples prior to actually designing the class. Then try to answer these questions:

• What data does the object keep track of? (fields)
• What should the object look like when it is created? (constructor)
• How can code outside access object information? (accessor methods)
• How can code outside modify object information? (modifier methods)
• What other actions should an object be able to take? (other methods)

Once you have a fairly good idea of the design, you should implement in stages:

• Set up the skeleton with a test main program.
• Add the data fields.
• Add the constructor.
• Add the print method.
• Test.
• Add the accessor methods and test.
• Add the modifier methods and test.
• Finish and do a thorough test.

Think about: What if denominator is zero?

The code developed in class can be found here

Quick Check Problems:

• Let x be 3 greater than y.
• Let x be the greater of y and z.
• Swap the values of x and y.