In this HackerRank Day 4: Class vs. Instance problem solution 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:
1. yearPasses() should increase the age instance variable by 1.
2. amIOld() should perform the following conditional actions:
3. If age < 13, print You are young..
4. If age >= 13 and age < 18, print You are a teenager..
5. Otherwise, print You are old..

## Problem solution in Python programming.

```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 = self.age + 1```

### Problem solution in Java programming.

```public class Person {
private int age;

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

}

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

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

### Problem solution in C++ programming.

```class Person{
public:
int age ;
Person(int initialAge);
void amIOld();
void yearPasses();
};
Person::Person(int initialAge){
// Add some more code to run some checks on initialAge
if (initialAge < 0) {
age = 0;
cout << "Age is not valid, setting age to 0." << endl;
} else {
age = initialAge;
}
}
void Person::amIOld(){
// Do some computations in here and print out the correct statement to the console
switch (age) {
case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8: case 9: case 10: case 11: case 12:
cout << "You are young." << endl;
break;
case 13: case 14: case 15: case 16: case 17:
cout << "You are a teenager." << endl;
break;
default:
cout << "You are old." << endl;
break;
}
}

void Person::yearPasses(){
// Increment the age of the person in here
age++;
}```

### Problem solution in Javascript programming.

```function Person(initial_Age){
if (initial_Age<0){
console.log('Age is not valid, setting age to 0.')
initial_Age = 0;
}
this.age = initial_Age;
}
Person.prototype.amIOld = function() {
if (this.age < 13)
console.log('You are young.');
else if (this.age < 18)
console.log('You are a teenager.');
else
console.log('You are old.');
}

Person.prototype.yearPasses = function() {
this.age++;
}```