pragma solidity ^0.4.18;

contract Owned {
    address owner;

    function Owned() public {
        owner = msg.sender;
    }

   modifier onlyOwner {
       require(msg.sender == owner);
       _;
   }
}

contract Courses is Owned {

    struct Instructor {
        uint age;
        bytes16 fName;
        bytes16 lName;
    }

    mapping (address => Instructor) instructors;
    address[] public instructorAccts;

    event instructorInfo(
       bytes16 fName,
       bytes16 lName,
       uint age
    );

    function setInstructor(address _address, uint _age, bytes16 _fName, bytes16 _lName) onlyOwner public {
        var instructor = instructors[_address];

        instructor.age = _age;
        instructor.fName = _fName;
        instructor.lName = _lName;

        instructorAccts.push(_address) -1;
        instructorInfo(_fName, _lName, _age);
    }

    function getInstructors() view public returns(address[]) {
        return instructorAccts;
    }

    function getInstructor(address _address) view public returns (uint, bytes16, bytes16) {
        return (instructors[_address].age, instructors[_address].fName, instructors[_address].lName);
    }

    function countInstructors() view public returns (uint) {
        return instructorAccts.length;
    }

}