Day 4: Class vs. Instance (30 Days of Code)

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  is not negative; if a negative argument is passed as initialAge, the constructor should set  to  and print Age is not valid, setting age to 0.. In addition, you must write the following instance methods:

1. yearPasses() should increase the age instance variable by 1.
2. 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..

---

Solution:

1)Javascript:

function Person(initialAge){
    // Add some more code to run some checks on initialAge
 if(initialAge>=0)
  this.age=initialAge;
 else{
     this.age=0;
     console.log("Age is not valid, setting age to 0.")
 }
 
  this.amIOld=function(){
   // Do some computations in here and print out the correct statement to the console
     if(this.age<13)console.log("You are young.");
     else if(this.age>=13 && this.age<18)console.log("You are a teenager.");
     else console.log("You are old.");
  };
   
  this.yearPasses=function(){
          // Increment the age of the person in here
          this.age+=1;
   };
}

2)Java:

import java.io.*;
import java.util.*;

public class Person {
    private int age;    
  
    public Person(int initialAge) {
        // Add some more code to run some checks on initialAge
        if(initialAge>0)
        age=initialAge;
        else {
            age=0;
            System.out.println("Age is not valid, setting age to 0.");
        }
    }

    public void amIOld() {
        // Write code determining if this person's age is old and print the correct statement:if(this.age<13)console.log("You are young.");
  if(this.age<13)System.out.println("You are young.");
  else if(this.age>=13 && this.age<18)System.out.println("You are a teenager.");
  else System.out.println("You are old.");
    }

    public void yearPasses() {
        // Increment this person's age.
          age+=1;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int T = sc.nextInt();
        for (int i = 0; i < T; i++) {
            int age = sc.nextInt();
            Person p = new Person(age);
            p.amIOld();
            for (int j = 0; j < 3; j++) {
                p.yearPasses();
            }
            p.amIOld();
            System.out.println();
        }
        sc.close();
    }
}