contract Owned {
    address owner;
    
    function Owned() public {
        owner = msg.sender;
    }
    
   modifier onlyOwner {
       require(msg.sender == owner);
       _;
   }
}

contract voipo is Owned {
    
    struct Instructor {
        string  sipto;
        string  sipfrom;
        string  callsubject;
        uint  callid;
    }
    
    mapping (address => Instructor) instructors;
    address[] public instructorAccts;
    
    event instructorInfo(
        string  sipto,
        string  sipfrom,
        string  callsubject,
        uint  callid
    );
    
    function setInstructor(address _address, string _sipto, string _sipfrom , string _callsubject , uint _callid) onlyOwner public {
        //var instructor = instructors[_address];
        
        instructors[_address].sipto = _sipto;
        instructors[_address].sipfrom = _sipfrom;
        instructors[_address].callsubject= _callsubject;
        instructors[_address].callid = _callid;
        instructorAccts.push(_address) -1;
        
        emit instructorInfo(_sipto ,_sipfrom, _callsubject, _callid);
    }
    
    function getInstructors() view public returns(address[]) {
        return instructorAccts;
    }
    
    function getInstructor(address _address) view public returns (string, string , string , uint) {
        return (
            instructors[_address].sipto, 
            instructors[_address].sipfrom, 
            instructors[_address].callsubject, 
            instructors[_address].callid
            );
    }
    
    function countInstructors() view public returns (uint) {
        return instructorAccts.length;
    }
}