公排互助拆分系统开发（案例开发），3M/DAPP拆分公排互助系统开发（开发逻辑）及源码

　　区块链技术可以构建一个高效可靠的价值传输系统，推动互联网成为构建社会信任的网络基础设施，实现价值的有效传递，并将此称为价值互联网。区块链提供了一种新型的社会信任机制，为数字经济的发展奠定了新基石，

　　什么是智能合约DApp。智能合约DApp是使用区块链技术实现去中心化应用(DApp)的核心技术。所谓智能合约是指以数字代码的形式编写的自动执行计算机程序，A smart contract system that automatically executes and manages the rights and interests of all parties that collaborate with each other.

　　在区块链中，每个块包含了一定数量的交易信息和该块的唯一标识符，同时还包含了前一个块的哈希值。这样的设计保证了区块之间的顺序和完整性，一旦一个块被添加到区块链中，它就不可更改。This makes blockchain a secure and trustworthy distributed ledger that can be used to record and verify various types of transactions.

　　//this low-level function should be called from a contract which performs important safety checks

　　function burn(address to)external lock returns(uint amount0,uint amount1){

　　(uint112 _reserve0,uint112 _reserve1,)=getReserves();//gas savings

　　address _token0=token0;//gas savings

　　address _token1=token1;//gas savings

　　uint balance0=IERC20(_token0).balanceOf(address(this));

　　uint balance1=IERC20(_token1).balanceOf(address(this));

　　uint liquidity=balanceOf[address(this)];

　　bool feeOn=_mintFee(_reserve0,_reserve1);

　　uint _totalSupply=totalSupply;//gas savings,must be defined here since totalSupply can update in _mintFee

　　//计算返回的amount0/1

　　amount0=liquidity.mul(balance0)/_totalSupply;//using balances ensures pro-rata distribution

　　amount1=liquidity.mul(balance1)/_totalSupply;//using balances ensures pro-rata distribution

　　require(amount0>0&&amount1>0,'UniswapV2:INSUFFICIENT_LIQUIDITY_BURNED');

　　_burn(address(this),liquidity);

　　//_token0/1给to转amount0/1

　　_safeTransfer(_token0,to,amount0);

　　_safeTransfer(_token1,to,amount1);

　　//获取转账后的balance

　　balance0=IERC20(_token0).balanceOf(address(this));

　　balance1=IERC20(_token1).balanceOf(address(this));

　　//更新reserve0,reserve1和时间戳

　　_update(balance0,balance1,_reserve0,_reserve1);

　　if(feeOn)kLast=uint(reserve0).mul(reserve1);//reserve0 and reserve1 are up-to-date

　　emit Burn(msg.sender,amount0,amount1,to);

　　}

　　//this low-level function should be called from a contract which performs important safety checks

　　//交易函数

　　//可以是token0-->token1,

　　//也可以是token1-->token0

　　//但参数中：amount0Out和amount1Out中有一个值是0

　　function swap(

　　uint amount0Out,

　　uint amount1Out,

　　address to,

　　bytes calldata data

　　)external lock

　　{

　　require(amount0Out>0||amount1Out>0,'UniswapV2:INSUFFICIENT_OUTPUT_AMOUNT');

　　(uint112 _reserve0,uint112 _reserve1,)=getReserves();//gas savings

　　require(amount0Out<_reserve0&&amount1Out<_reserve1,'UniswapV2:INSUFFICIENT_LIQUIDITY');

　　uint balance0;

　　uint balance1;

　　{//scope for _token{0,1},avoids stack too deep errors

　　address _token0=token0;

　　address _token1=token1;

　　require(to!=_token0&&to!=_token1,'UniswapV2:INVALID_TO');

　　//划转操作

　　if(amount0Out>0)_safeTransfer(_token0,to,amount0Out);//optimistically transfer tokens

　　if(amount1Out>0)_safeTransfer(_token1,to,amount1Out);//optimistically transfer tokens

　　if(data.length>0)IUniswapV2Callee(to).uniswapV2Call(msg.sender,amount0Out,amount1Out,data);

　　balance0=IERC20(_token0).balanceOf(address(this));

　　balance1=IERC20(_token1).balanceOf(address(this));

　　}

　　uint amount0In=balance0>_reserve0-amount0Out?balance0-(_reserve0-amount0Out):0;

　　uint amount1In=balance1>_reserve1-amount1Out?balance1-(_reserve1-amount1Out):0;

　　require(amount0In>0||amount1In>0,'UniswapV2:INSUFFICIENT_INPUT_AMOUNT');

　　{//scope for reserve{0,1}Adjusted,avoids stack too deep errors

　　//防止数据溢出校验

　　uint balance0Adjusted=balance0.mul(1000).sub(amount0In.mul(3));

　　uint balance1Adjusted=balance1.mul(1000).sub(amount1In.mul(3));

　　require(balance0Adjusted.mul(balance1Adjusted)>=uint(_reserve0).mul(_reserve1).mul(1000**2),'UniswapV2:K');

　　}