# Day 12: Inheritance | 30 Days Of Code | HackerRank Solution

Hello coders, today we are going to solve Day 12: Inheritance HackerRank Solution in C++, Java and Python.

Contents

## Objective

Today, we’re delving into Inheritance.

You are given two classes, Person and Student, where Person is the base class and Student is the derived class. Completed code for Person and a declaration for Student are provided for you in the editor. Observe that Student inherits all the properties of Person.

Complete the Student class by writing the following:

• Student class constructor, which has 4 parameters:
1. A string, firstName.
2. A string, lastName.
3. An integer, idNumber.
4. An integer array (or vector) of test scores, scores.
• char calculate() method that calculates a Student object’s average and returns the grade character representative of their calculated average:

## Input Format

The locked stub code in the editor reads the input and calls the Student class constructor with the necessary arguments. It also calls the calculate method which takes no arguments.

The first line contains firstnamelastName, and idNumber, separated by a space. The second line contains the number of test scores. The third line of space-separated integers describes scores.

## Constraints

• 1 <= length of firstName, length of lastName <= 10
• length of idNumber = 7
• 0 <= score <= 100

## Output Format

Output is handled by the locked stub code. Your output will be correct if your Student class constructor and calculate() method are properly implemented.

Sample Input

``````Heraldo Memelli 8135627
2
100 80``````

Sample Output

`````` Name: Memelli, Heraldo
ID: 8135627

Explanation

This student had 2 scores to average: 100 and 80. The student’s average grade is (100 + 800) / 2 = 90. An average grade of 90 corresponds to the letter grade O, so the calculate() method should return the character`'O'`.

## Solution – Day 12: Inheritance

### C++

```#include <iostream>
#include <vector>

using namespace std;

class Person{
protected:
string firstName;
string lastName;
int id;
public:
Person(string firstName, string lastName, int identification){
this->firstName = firstName;
this->lastName = lastName;
this->id = identification;
}
void printPerson(){
cout<< "Name: "<< lastName << ", "<< firstName <<"\nID: "<< id << "\n";
}

};
class Student : public Person {
private:
vector<int> testScores;
public:
Student(string firstName, string lastName, int id, vector<int> scores) : Person(firstName, lastName, id) {
this->testScores = scores;
}
// Write char calculate()
char calculate() {
int total = 0;

for (int i = 0; i < this->testScores.size(); i++)
total += this->testScores[i];

int avg = (int) (total / testScores.size());
if (avg >= 90 && avg <= 100) return 'O';
if (avg >= 80 && avg < 90) return 'E';
if (avg >= 70 && avg < 80) return 'A';
if (avg >= 55 && avg < 70) return 'P';
if (avg >= 40 && avg < 55) return 'D';
return 'T';
}
};
int main() {
string firstName;
string lastName;
int id;
int numScores;
cin >> firstName >> lastName >> id >> numScores;
vector<int> scores;
for(int i = 0; i < numScores; i++){
int tmpScore;
cin >> tmpScore;
scores.push_back(tmpScore);
}
Student* s = new Student(firstName, lastName, id, scores);
s->printPerson();
cout << "Grade: " << s->calculate() << "\n";
return 0;
}```

### Java

```import java.util.Scanner;

class Person {

protected String firstName;

protected String lastName;
protected int idNumber;
// Constructor

Person(String firstName, String lastName, int identification) {
this.firstName = firstName;
this.lastName = lastName;
this.idNumber = identification;
}
// Print person data
public void printPerson() {
System.out.println("Name: " + lastName + ", " + firstName + "\nID: " + idNumber);
}
}
class Student extends Person {

private int[] testScores;

Student(String firstName, String lastName, int identification, int[] testScores) {

super(firstName, lastName, identification);
this.testScores = testScores;
}

char calculate() {
int total = 0;

for (int testScore : testScores) total += testScore;

int avg = total / testScores.length;
if (avg >= 90 && avg <= 100) return 'O';
if (avg >= 80 && avg < 90) return 'E';
if (avg >= 70 && avg < 80) return 'A';
if (avg >= 55 && avg < 70) return 'P';
if (avg >= 40 && avg < 55) return 'D';
return 'T';
}
}

public class Solution {

public static void main(String[] args) {

Scanner scan = new Scanner(System.in);
String firstName = scan.next();
String lastName = scan.next();
int id = scan.nextInt();
int numScores = scan.nextInt();
int[] testScores = new int[numScores];
for (int i = 0; i < numScores; i++) {
testScores[i] = scan.nextInt();
}
scan.close();
Student s = new Student(firstName, lastName, id, testScores);
s.printPerson();
}
}```

### Python

```class Person:
def __init__(self, firstName, lastName, idNumber):
self.firstName = firstName
self.lastName = lastName
self.idNumber = idNumber
def printPerson(self):
print("Name:", self.lastName + ",", self.firstName)
print("ID:", self.idNumber)
class Student(Person):
def __init__(self, firstName, lastName, idNumber, testScores):
super().__init__(firstName, lastName, idNumber)
self.testScores = testScores

def calculate(self):
total = 0

for testScore in self.testScores:
total += testScore

avg = total / len(self.testScores)

if 90 <= avg <= 100:
return 'O'
if 80 <= avg < 90:
return 'E'
if 70 <= avg < 80:
return 'A'
if 55 <= avg < 70:
return 'P'
if 40 <= avg < 55:
return 'D'
return 'T'
line = input().split()
firstName = line
lastName = line
idNum = line
numScores = int(input()) # not needed for Python
scores = list( map(int, input().split()) )
s = Student(firstName, lastName, idNum, scores)
s.printPerson()