Практика 6

<?php
	class student 
	{
		public  $fio;
        public  $subjects; 
        public  $gender;
        public  $group;
        public function __construct(string $fio, array $subjects, string $gender, string $group) 
		{
            $this->fio = $fio;
            $this->subjects = $subjects;
            $this->gender = $gender;
			$this->group = $group;
        }
		public function GetaverageScore ()
		{
			$averageScore = array_sum( $this->subjects) / count($this->subjects);
			return $averageScore;
		}
        
	}

$students = [
	      new Student("Иванов Иван", ["Математика"=>100,'Русский'=>25,'Информатика'=>85], "Мужчина", "ЭУ-247"),
          new Student("Петров Анатолий", ["Математика"=>90,'Русский'=>30,'Информатика'=>70], "Мужчина", "ЭУ-247"),
          new Student("Сидоров Сегрей", ["Математика"=>50,'Русский'=>90,'Информатика'=>40], "Мужчина", "ЭУ-247"),
	    ];

usort($students, "cmp");
function cmp($studentA, $studentB)
{   
	$A=$studentA->GetaverageScore();
	$B=$studentB->GetaverageScore();
    if ($A == $B) 
	{
        return 0;
    }
    return ($A < $B) ? 1 : -1;
}

echo "<ul>";
foreach ($students as $student) {
    echo '<li>' . $student->fio . ': ' . $student->GetaverageScore() . '</li>';
}
echo "</ul>";
			
?>

Results:

Иванов Иван: 70
Петров Анатолий: 63.333333333333
Сидоров Сегрей: 60