SimpleLotto.sol

pragma solidity ^0.4.4;

contract Lotto {
    
    uint constant public maxTickets = 5;
    uint public currentTickets = 0;
    
    mapping(uint=>address) participants;
    
    event logString(string x);
    event logUint(uint x);
    event logAddress(address x);
    
    uint constant public ticketPrice = 100000000000000000;
    // the cost of each ticket is .1 ether.
    
    function rand() returns(uint) { 
        uint decisionBlockHash = uint(block.blockhash(block.number-1));
        return decisionBlockHash%maxTickets;
    }

    function payout() {
        // Game is over
        if (currentTickets != maxTickets) {
            throw;
        }
        // Calulate winner
        uint winner = rand();
        
        // Set your state BEFORE sending your money!
        currentTickets = 0;
        
        // Send money to the winner
        bool rv = participants[winner].send(ticketPrice*maxTickets);
        
        logString("Winner prize sent:");
        logUint(winner);
        logString("Winner address:");
        logAddress(participants[winner]);
        
        // Throw if some monkey buisness is going on
        if (rv == false) {
            throw;
        }
        
    }

    function() {
        if (msg.value != ticketPrice) {
            throw;
        }
        if (currentTickets == maxTickets){
            this.payout();
        }
        participants[currentTickets] = msg.sender;
        currentTickets = currentTickets + 1;
        logString("A ticket was added");
        logUint(currentTickets);
    }

}