区块链技术（三）：智能合约入门

contract ZhaoxiStorage {
    uint storedData;
    function set(uint x) {        storedData = x;    }
    function get() constant returns (uint retVal) {        return storedData;    }}

contract ZhaoxiCoin {
    // 关键字“public”使变量能从合约外部访问。    address public minter;    mapping (address => uint) public balances;
    // 事件让轻客户端能高效的对变化做出反应。    event Sent(address from, address to, uint amount);
    // 这个构造函数的代码仅仅只在合约创建的时候被运行。    function ZhaoxiCoin() {        minter = msg.sender;    }
    // 合约创建者可以调用mint    function mint(address receiver, uint amount) {        if (msg.sender != minter) return;        balances[receiver] += amount;    }
    // send可以被拥有代币的任何人调用    function send(address receiver, uint amount) {        if (balances[msg.sender] < amount) return;        balances[msg.sender] -= amount;        balances[receiver] += amount;        Sent(msg.sender, receiver, amount);    }}

function minter() returns (address) { return minter; }

function balances(address _account) returns (uint balance) {    return balances[_account];}

ZhaoxiCoin.Sent().watch({}, '', function(error, result) {    if (!error) {        console.log("ZhaoxiCoin transfer: " + result.args.amount +            " coins were sent from " + result.args.from +            " to " + result.args.to + ".");        console.log("Balances now:\n" +            "Sender: " + ZhaoxiCoin.balances.call(result.args.from) +            "Receiver: " + ZhaoxiCoin.balances.call(result.args.to));    }}