以下是一个简单的以太坊竞猜合约示例:
pragma solidity ^0.8.0;
contract BettingContract {
address public owner;
uint public nonce;
uint public lastBlock;
event Bet(address player, uint betAmount, uint blockNumber);
event Win(address player, uint betAmount, uint blockNumber);
function bet(uint amount) public payable returns (bool) {
require(block.number > lastBlock, "Too early");
require(msg.value >= amount, "Not enough ether");
nonce++;
address player = msg.sender;
uint bet = amount;
require(player.send(bet), "Send failed");
emit Bet(player, bet, block.number);
if (nonce == 1000) {
uint winner = randomNumber(player);
emit Win(winner, bet, block.number);
lastBlock = block.number;
}
return true;
}
function randomNumber(address player) private returns (uint) {
// Generate a random number between 1 and 1000
}
}
这个合约包含了一个公共的owner地址,用于管理合约。nonce是一个公共变量,用于跟踪合约收到的赌注数量。lastBlock是一个公共变量,用于跟踪最后一个获胜者的赌注。合约还包含了两个事件,Bet和Win,用于记录赌注和获胜者的信息。
bet函数是一个公共函数,用于接收玩家的赌注。它首先检查赌注是否足够,然后增加nonce计数器,记录玩家和赌注金额,并将赌注发送回玩家的地址。如果nonce等于1000,合约将生成一个随机数,并选择一个获胜者。获胜者将收到他的赌注,并将lastBlock设置为当前区块号码。最后,函数返回true表示赌注已成功下注。