隨堂上機考 (2)

Write a program to implement a method that can do additions of 2 fractions. You will implement a class called Fraction consisting of a numerator and a denominator. The additions of
2 fractions should be equal to a fraction.
Use 1/2+1/3 as the test.

Hints:
Fraction f1, f2;
f1.add(f2);