区块链踩坑之智能合约代币编写及使用介绍

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前言

上篇文章我们搭建了以太坊网络私有链，实现了多节点间的转账交易以及了解和使用了多重签名钱包。本篇我们将继续深挖，共同探讨智能合约部分。首先我们要编写以太坊的只能合约，那就得先了解下Solitidy 语言。戳官网 http://solidity.readthedocs.io/en/develop/index.html

Solitidy简单介绍：

●它是一个面向合约的高级语言，其语法类似于JavaScript。是运行在以太坊虚拟机中的代码。

●它是静态类型的编程语言，编译期间会检查其数据类型。支持继承、类和复杂的用户定义类型。

●在线体验：https://remix.ethereum.org

一个面向数字加密货币最简单的合约代码示例如下：

pragma solidity ^0.4.21;

contract Coin {
    // The keyword "public" makes those variables
    // readable from outside.
    address public minter;
    mapping (address => uint) public balances;

    // Events allow light clients to react on
    // changes efficiently.
    event Sent(address from, address to, uint amount);

    // This is the constructor whose code is
    // run only when the contract is created.
    function Coin() public {
        minter = msg.sender;
    }

    function mint(address receiver, uint amount) public {
        if (msg.sender != minter) return;
        balances[receiver] += amount;
    }

    function send(address receiver, uint amount) public {
        if (balances[msg.sender] < amount) return;
        balances[msg.sender] -= amount;
        balances[receiver] += amount;
        emit Sent(msg.sender, receiver, amount);
    }
}