Day 4: Class vs. Instance | 30 Days of Code | Hackerrank Solution

Hello coders,

Today we are going to solve Class vs. Instance which is the fourth day problem of our Hackerrank 30 Day Code challenge.

Classes are one of the most important topic in programming. So, it is must to know about this topic.

So, Without Further Ado let's jump into the question.

Day 4: Class vs. Instance | 30 Days of Code | Hackerrank Solution

1 Objective
2 Task
3 Input Format
4 Output Format
5 Solution - Class vs. Instance
6 Conclusion

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's only enabled 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, settings age to 0 . . .

In addition, you must write the following instance methods:

1. yearPasses() should increase the age instance variable by 1.

2. amlOld() 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 . . .

To help you learn by example and complete this challenge, much of the code is provided for you, but you'll be writing everything in the future. The code that creates each instance of your person is in the main method. Don't worry if you don't understand it all quite yet!

Note: Do not remove or alter the stub code in the editor.

Input Format

Input is handled for you by the stub code in the editor.

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

Complete the method definitions provided in the editor so they meet the specifications outlined above; the code to test your work is already in the editor. 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

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.

The extra line at the end of the output is supposed to be there and is trimmed before being compared against the test case's expected output. If you're failing this challenge, check your logic and review your print statements for spelling errors.

Solution - Day 4: Class vs. Instance

Python 3 Solution

class Person:
    def __init__(self,initialAge):
        # Add some more code to run some checks on initialAge
        if (initialAge < 0):
            print("Age is not valid, setting age to 0.")
            self.age = 0
        else:
            self.age = initialAge    
    def amIOld(self):
        # Do some computations in here and print out the correct statement to the console
        if ( self.age < 13 ):
            print("You are young.")
        elif ( self.age >= 13 and self.age < 18 ):
            print("You are a teenager.")
        else:
            print("You are old.")        
    def yearPasses(self):
        # Increment the age of the person in here
        self.age += 1
t = int(input())
for i in range(0, t):
    age = int(input())         
    p = Person(age)  
    p.amIOld()
    for j in range(0, 3):
        p.yearPasses()       
    p.amIOld()
    print("")

Class vs. Instance - Solution

Class vs. Instance - Result

Conclusion

This was the solution of our Day 4: Class vs. Instance problem. If you are getting errors while running the program check the spelling, lowercase and uppercase carefully.

If you have any doubt regarding the problem ( Day 4: Class vs. Instance ), feel free to contact in the Comment section.

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Disclaimer: The above problem is generated by Hacker Rank but the solution is provided by Sloth Coders.

Happy Coding!!

A Sloth Who loves to Code.

Sloth Coders

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Day 4: Class vs. Instance | 30 Days of Code | Hackerrank Solution