本文主要是介绍Soildity之示例合约分析（7），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
之前有同事转行做区块链钱包方面的开发，在18年上半年币市大伙的时候，在以太坊主链上部署了一个智能合约发行代码，今天就通过 https://etherscan.io/ 网站通过智能约合地址来撸一下智能合约的代码，源码如下：
pragma solidity ^0.4.16;//基类合约
contract Ownable {address public owner;function Ownable() public {owner = msg.sender;//构造函数，对owner进行赋值，部署合约的发起方}modifier onlyOwner() {//函数修改器，调用_;函数体必须满足 msg.sender == owner 条件require(msg.sender == owner);_;}function transferOwnership(address newOwner) public onlyOwner {if (newOwner != address(0)) {//修改合约的部署方账号地址owner = newOwner;}}}contract SafeMath {function safeSub(uint a, uint b) pure internal returns (uint) {//针对减法做安全性判断，适用于转账，转账发起方账户余额大于转账金额sAssert(b <= a);return a - b;}function safeAdd(uint a, uint b) pure internal returns (uint) {//针对加法做安全性判断，适用于转账，防止大额转账接收方数据溢出uint c = a + b;sAssert(c>=a && c>=b);return c;}function sAssert(bool assertion) internal pure {if (!assertion) {revert(); //发生错误，进行状态回滚}}
}contract ERC20 {//发现代币的总额uint public totalSupply;//查询账户代币的余额function balanceOf(address who) public constant returns (uint);//查询owner账户可对spender账户进行代币转账操作的余额function allowance(address owner, address spender) public constant returns (uint);//转账function transfer(address toAcct, uint value) public returns (bool ok);function transferFrom(address fromAcct, address toAcct, uint value) public returns (bool ok);//额度设置函数function approve(address spender, uint value) public returns (bool ok);//定义两个事件，用于通知客户端event Transfer(address indexed fromAcct, address indexed toAcct, uint value);event Approval(address indexed owner, address indexed spender, uint value);
}contract StandardToken is ERC20, SafeMath {//记录所有账户余额的映射mapping(address => uint) balances;mapping (address => mapping (address => uint)) allowed;//转账实现function transfer(address _toAcct, uint _value) public returns (bool success) {balances[msg.sender] = safeSub(balances[msg.sender], _value);balances[_toAcct] = safeAdd(balances[_toAcct], _value);//触发事件Transfer(msg.sender, _toAcct, _value);return true;}//转账实现function transferFrom(address _fromAcct, address _toAcct, uint _value) public returns (bool success) {//获取账户能够进行转账的额度var _allowance = allowed[_fromAcct][msg.sender];//进行转账相关账户余额的安全性验证balances[_toAcct] = safeAdd(balances[_toAcct], _value);balances[_fromAcct] = safeSub(balances[_fromAcct], _value);//对可进行转账的余额进行修改allowed[_fromAcct][msg.sender] = safeSub(_allowance, _value);//触发事件Transfer(_fromAcct, _toAcct, _value);return true;}//查询账户余额function balanceOf(address _owner) public constant returns (uint balance) {return balances[_owner];}function approve(address _spender, uint _value) public returns (bool success) {//设置msg.sender可以对_spender账户进行代币转账的总额度allowed[msg.sender][_spender] = _value;//触发事件Approval(msg.sender, _spender, _value);return true;}//查询可进行代币转账的余额function allowance(address _owner, address _spender) public constant returns (uint remaining) {return allowed[_owner][_spender];}}contract BcnCoin is Ownable, StandardToken {string public name;string public symbol;uint public decimals; uint public totalSupply; //构造函数，对代币进行初始化配置function BcbCoin() public {totalSupply = 2000 * (10**6) * (10**18); balances[msg.sender] = totalSupply;name = "BCN";symbol = "BCN";decimals = 18; }//可接收以太币转账的fallback函数function () payable public{}//代币发行方进行账户变更function transferOwnership(address _newOwner) public onlyOwner {balances[_newOwner] = safeAdd(balances[owner], balances[_newOwner]);balances[owner] = 0;Ownable.transferOwnership(_newOwner);}// Owner can transfer out any ERC20 tokens sent in by mistakefunction transferAnyERC20Token(address tokenAddress, uint amount) public onlyOwner returns (bool success){return ERC20(tokenAddress).transfer(owner, amount);}}
以上是对源码的全部解释。看完也感觉合约也不是那样的神秘，其实也就是一段代码！
推荐一个比较全面的合约代码：https://www.jianshu.com/p/0d0dd2f09c99
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