using System;

​

class Person {

    public int age;     

    public Person(int initialAge) {

        // Add some more code to run some checks on initialAge

        if(initialAge < 0)

        {

            this.age = 0;

            Console.WriteLine("Age is not valid, setting age to 0.");

        }

        else

        {

            this.age=initialAge;

        }

     }

     public void amIOld() {

        // Do some computations in here and print out the correct statement to the console 

        if(this.age<13)

        {

            Console.WriteLine("You are young.");

        }

        else if(this.age >= 13 && this.age <18)

        {

            Console.WriteLine("You are a teenager.");

        }

        else{

            Console.WriteLine("You are old.");

        }

     }

​

     public void yearPasses() {

        // Increment the age of the person in here

        this.age++;

     }

​

static void Main(String[] args) {

        int T=4;

    int[] ages = new int[] {-1, 10, 16, 18};

        for (int i = 0; i < T; i++) {

            int age=ages[i];

            Person p=new Person(age);

             p.amIOld();

                for (int j = 0; j < 3; j++) {

                  p.yearPasses();

                }

                p.amIOld();

                Console.WriteLine();

        }

    }

}

​