pragma solidity ^0.4.21; contract PredictTheFutureChallenge { address guesser; uint8 guess; uint256 settlementBlockNumber; function PredictTheFutureChallenge() public payable { require(msg.value == 1 ether); } function isComplete() public view returns (bool) { return address(this).balance == 0; } function lockInGuess(uint8 n) public payable { require(guesser == 0); require(msg.value == 1 ether); guesser = msg.sender; guess = n; settlementBlockNumber = block.number + 1; } function settle() public { require(msg.sender == guesser); require(block.number > settlementBlockNumber); uint8 answer = uint8(keccak256(block.blockhash(block.number - 1), now)) % 10; guesser = 0; if (guess == answer) { msg.sender.transfer(2 ether); } } }
0.4.21