Métodos Getter, Setter e Construtor

index.PHP

<!DOCTYPE html>
<html lang="pt-br">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <?php 
        require_once 'Caneta.php';
        $c1 = new Caneta("BIC", "Azul", 0.5);
        $c1 = new Caneta("KKK", "Verde", 1.0);
    ?>
</body>
</html>

Caneta.PHP

<?php 
    class Caneta {
        public $modelo;
        private $cor;
        private $ponta;
        private $tampada;
        public function Caneta($m, $c, $p)
        {
            $this->modelo = $m;
            $this->cor = $c;
            $this->ponta = $p;
            $this->tampar();
        }
        public function tampar() {
            $this->tampada = true;
        }
        public function getModelo() {
            return $this->modelo;
        }
        public function setModelo($m) {
            $this->modelo = $m;
        }
        public function getPonta() {
            return $this->ponta;
        }
        public function setPonta($p) {
            $this->ponta = $p;
        }
    }
?>