Parse error: syntax error, unexpected 'if' (T_IF) in C: \ xampp \ htdocs \ Web System \ conexion.php on line 17

This error is indicated to me, but I can not make it work. I attach the connection code.php

class Conexion
{

    public function __construct($server, $nameBD , $user , $pass)
    {
        $con = mysql_connect($server, $user , $pass);


        if (!$con) {
            die("Error al conectar:".mysql_error());
        }


        $selBD = mysql_select_db($nameBD);

        if (!$selBD) {
            die("Error al seleccionar la BD:".mysql_error());
        }
    }



    public function ejecutar ($query){

        return mysql_query($query);
    }
}