Day 4 - Class vs. Instance

Objective

In this challenge, we’re going to learn about the difference between a class and an instance; because this is an Object Oriented concept, it can be done only in certain languages.

Task

Write a Person class with an instance variable, age, and a constructor that takes an integer, initialAge, as a parameter. The constructor must assign initialAge to age after confirming the argument passed as initialAge is not negative; if a negative argument is passed as initialAge, the constructor should set age to 0 and print ‘Age is not valid, setting age to 0.’. In addition, you must write the following instance methods:

yearPasses() should increase the age instance variable by 1. amIOld() should perform the following conditional actions: If age<13, print ‘You are young.’. If age>=13 and age<18, print ‘You are a teenager.’. Otherwise, print ‘You are old.’.

Input Format

The first line contains an integer, T (the number of test cases), and the T subsequent lines each contain an integer denoting the age of a Person instance.

Constraints

1<=T<=4
-5<=age<=30

Output Format

If your methods are implemented correctly, each test case will print 2 or 3 lines (depending on whether or not a valid initialAge was passed to the constructor).

Sample Input

4
-1
10
16
18

Sample Output

Age is not valid, setting age to 0.
You are young.
You are young.

You are young.
You are a teenager.

You are a teenager.
You are old.

You are old.
You are old.

Explanation

Test Case 0: initialAge=-1
Because initialAge<0, our code must set age to 0 and print the ‘Age is not valid…’ message followed by the young message. Three years pass and age=3, so we print the young message again.

Test Case 1: initialAge=10 Because initialAge<13, our code should print that the person is young. Three years pass and age=13, so we print that the person is now a teenager.

Test Case 2: initialAge=16 Because 13<=initialAge<18, our code should print that the person is a teenager. Three years pass and age=19, so we print that the person is old.

Test Case 3: initialAge=18 Because initialAge>=18, our code should print that the person is old. Three years pass and the person is still old at age=21, so we print the old message again.