Day 12: Inheritance

https://www.hackerrank.com/challenges/30-inheritance/problem

class Student extends person {
    private $testScores;
    /*
    *   Class Constructor
    *
    *   Parameters:
    *   firstName - A string denoting the Person's first name.
    *   lastName - A string denoting the Person's last name.
    *   id - An integer denoting the Person's ID number.
    *   scores - An array of integers denoting the Person's test scores.
    */
    // Write your constructor here
    public $first_name, $last_name, $id, $scores;
    function __construct($_first_name, $_last_name, $_id, $_scores){
        $this->first_name = $_first_name;
        $this->last_name = $_last_name;
        $this->id = $_id;
        $this->scores = $_scores;
    }

    function printPerson(){
        print("Name: ".$this->last_name.", ".$this->first_name."\n");
        print("ID: ".$this->id."\n");
    }

    /*
    *   Function Name: calculate
    *   Return: A character denoting the grade.
    */
    // Write your function here
    private $grade = ['O', 'E', 'A', 'P', 'D', 'T'];
    private $grade_score = [90, 80, 70, 55, 40, 0];
    function calculate(){
        $scores = $this->scores;
        $ever = 0;
        for($i=0; $i<count($scores); $i++){
            $ever+=$scores[$i];
        }
        $ever = $ever / count($scores);
        for($i=0; $i<count($this->grade); $i++){
            if($ever >= $this->grade_score[$i]){
                return $this->grade[$i];
            }
        }
    }
}