这是一个简单的set(),get()一个值的合约，并且还包括了一个发行代币的示例。
也有一些log的功能。
contract Token {
address issuer;
uint public tk;
mapping (address => uint) balances;
event Issue(address account, uint amount);
event Transfer(address from, address to, uint amount);
function Token() {
issuer = msg.sender;
}
function issue(address account, uint amount) {
if (msg.sender != issuer) throw;
balances[account] += amount;
}
function transfer(address to, uint amount) {
if (balances[msg.sender] < amount) throw;
balances[msg.sender] -= amount;
balances[to] += amount;
Transfer(msg.sender, to, amount);
}
function getBalance(address account) constant returns (uint) {
return balances[account];
}
function set_tk(uint a) public {
tk += a;
}
function get_tk() public constant returns (uint) {
return tk;
}
}contract TheLuckyOne {
address owner;
mapping(uint => address) public tickets; //All tickets, ever, in order
mapping(uint => uint) public winners; //All winners, ever, in order
uint public numTickets; //Number of tickets bought lifetime
uint public numWinners; //Number of pots awarded lifetime
uint public lastProcessed; //Last index of tickets processed
uint public lastBlock; //Last block of the round to be processed
bytes32 public clientSeed; //Client seed
bytes32 public curSecretHash; //Hash of server seed
bytes32 public lastBlockHash; //Block hash to use
bytes32 public lastClientSeed; //Client seed to use
uint public constant TICKETSPERROUND = 1000; //Number of tickets per round
uint public constant TIMEOUT = 24 hours;
uint public constant ETHERVAL = 1000000000000000000;
uint public deadlineStart; //Value of 0 means no deadline
event Log(uint value);
function TheLuckyOne(bytes32 initialSecretHash) {
curSecretHash = initialSecretHash;
owner = msg.sender;
}
//Withdraw excess funds, keeping enough for payouts
function adminWithdraw() {
if (msg.sender != owner) {
return;
}
//Can't withdraw the amount needed for payout
uint frozenValue = ((numTickets - lastProcessed) * ETHERVAL);
//Withdraw the rest
Log(this.balance - frozenValue);
msg.sender.send(this.balance - frozenValue);
}
//Get time in seconds since deadline, returns 1337 if no deadline
function getTimeElapsed() constant returns(uint) {
if (deadlineStart == 0) {
return 1337;
} else {
return block.timestamp - deadlineStart;
}
}
//Clone of sha3
function sha3clone(bytes32 input) constant returns (bytes32) {
return sha3(input);
}
//Return funds to players if server seed not released in time
function recoverLostFunds() {
//No deadline
if (deadlineStart == 0) {
return;
}
//Deadline not hit yet
if (block.timestamp - deadlineStart < TIMEOUT) {
return;
}
//Destroy the hash to prevent supplying a working seed at this phase
curSecretHash = 0;
uint toSend = 0;
//Calculate how much to pay based off tickets
for (var i = lastProcessed; i < numTickets; i++) {
if (tickets[i] == msg.sender) {
toSend += ETHERVAL;
}
}
//Refund full ticket value
msg.sender.send(toSend);
}
//Reveal seed and pay out last round
function revealAndPayout(bytes32 curSecret, bytes32 nextSecretHash) {
//Not admin
if (msg.sender != owner) {
return;
}
//Invalid Seed
if (sha3(curSecret) != curSecretHash || curSecretHash == 0) {
return;
}
//Payout premature
if (numTickets < TICKETSPERROUND ||
lastProcessed > numTickets - TICKETSPERROUND) {
return;
}
//Fetch the non-server sources of entropy
bytes32 serverClientHash = sha3(curSecret, lastClientSeed);
//Calculate winner and pay out
uint winnerIdx =
lastProcessed + uint(serverClientHash ^ lastBlockHash) % TICKETSPERROUND;
tickets[winnerIdx].send(TICKETSPERROUND * ETHERVAL);
Log (winnerIdx);
//Record win
winners[numWinners++] = winnerIdx;
//Update state variables for next pot
lastProcessed += TICKETSPERROUND;
//Reset deadline
deadlineStart = 0;
//Update seed
curSecretHash = nextSecretHash;
}
function () {
uint ticketsBought;
//Calculate tickets bought
//Price is 1.025 ETH per ticket for 25+ tickets
if (msg.value >= 25625 finney) {
ticketsBought = msg.value/1025000000000000000;
//Refund difference
msg.sender.send(msg.value % 1025000000000000000);
}
//Price is 1.050 ETH per ticket for 10+ tickets
else if (msg.value >= 10500 finney) {
ticketsBought = msg.value/1050000000000000000;
//Refund difference
msg.sender.send(msg.value % 1050000000000000000);
}
//Price is 1.100 ETH per ticket for 5+ tickets
else if (msg.value >= 5500 finney) {
ticketsBought = msg.value/1100000000000000000;
//Refund difference
msg.sender.send(msg.value % 1100000000000000000);
}
//Price is 1.150 ETH per ticket for 1+ tickets
else {
ticketsBought = msg.value/1150000000000000000;
//Refund difference
msg.sender.send(msg.value % 1150000000000000000);
}
//Update client seed
clientSeed = sha3(clientSeed, msg.sender, msg.value);
//If this is the final ticket, record the block and set the deadline
if (numTickets/TICKETSPERROUND != (numTickets + ticketsBought)/TICKETSPERROUND) {
lastBlock = block.number;
lastClientSeed = clientSeed;
deadlineStart = block.timestamp;
}
//Update blockhash (done here because of 256 timeout)
if (block.blockhash(lastBlock + 1) != 0) {
lastBlockHash = block.blockhash(lastBlock + 1);
}
//Buys a ticket for each ether
for (var i = 1; i <= ticketsBought; i += 1) {
tickets[numTickets++] = msg.sender;
}
}
}