二二複製公排開發規則丨二二複製公排系統開發（開發專案及原始碼）

　　

新零售o2o模式就是o2o模式和零售模式的結合，將零售行業的特點跟網際網路結合起來，實現線上線下的互通。

　　The new retail O2O model pays more attention to the combination of online and offline.The online platform increases exposure,leads traffic to offline,completes services online and offline,and gives users a better experience.

　　library UniswapV2Library{

　　using SafeMath for uint;

　　//returns sorted token addresses,used to handle return values from pairs sorted in this order

　　//給地址排序，從小到大

　　function sortTokens(address tokenA,address tokenB)internal pure returns(address token0,address token1){

　　require(tokenA!=tokenB,'UniswapV2Library:IDENTICAL_ADDRESSES');

　　(token0,token1)=tokenA<tokenB?(tokenA,tokenB):(tokenB,tokenA);

　　require(token0!=address(0),'UniswapV2Library:ZERO_ADDRESS');

　　}開發需求及細節：MrsFu123

　　//calculates the CREATE2 address for a pair without making any external calls

　　//在不進行任何外部呼叫的情況下計算一對的CREATE2地址

　　function pairFor(address factory,address tokenA,address tokenB)internal pure returns(address pair){

　　(address token0,address token1)=sortTokens(tokenA,tokenB);

　　pair=address(uint(keccak256(abi.encodePacked(

　　hex'ff',

　　factory,

　　keccak256(abi.encodePacked(token0,token1)),

　　hex'96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f'//init code hash

　　))));

　　}

　　//fetches and sorts the reserves for a pair

　　//獲取並排序一對的儲備

　　function getReserves(address factory,address tokenA,address tokenB)internal view returns(uint reserveA,uint reserveB){

　　(address token0,)=sortTokens(tokenA,tokenB);

　　(uint reserve0,uint reserve1,)=IUniswapV2Pair(pairFor(factory,tokenA,tokenB)).getReserves();

　　(reserveA,reserveB)=tokenA==token0?(reserve0,reserve1):(reserve1,reserve0);

　　}

　　//given some amount of an asset and pair reserves,returns an equivalent amount of the other asset

　　//給定一定數量的資產和配對準備金，返回等量的其他資產

　　//BB/AA=B/A-->BB=AA*(B/A)

　　function quote(uint amountA,uint reserveA,uint reserveB)internal pure returns(uint amountB){

　　require(amountA>0,'UniswapV2Library:INSUFFICIENT_AMOUNT');

　　require(reserveA>0&&reserveB>0,'UniswapV2Library:INSUFFICIENT_LIQUIDITY');

　　amountB=amountA.mul(reserveB)/reserveA;

　　}

　　//給定資產的輸入量和對儲備

　　//考慮手續費

　　//(x+0.997a)(y-b)=xy

　　//b=(0.997ay)/(x+0.997a)

　　//b=(997ay)/(1000x+997a)

　　function getAmountOut(uint amountIn,uint reserveIn,uint reserveOut)internal pure returns(uint amountOut){

　　require(amountIn>0,'UniswapV2Library:INSUFFICIENT_INPUT_AMOUNT');

　　require(reserveIn>0&&reserveOut>0,'UniswapV2Library:INSUFFICIENT_LIQUIDITY');

　　uint amountInWithFee=amountIn.mul(997);

　　uint numerator=amountInWithFee.mul(reserveOut);

　　uint denominator=reserveIn.mul(1000).add(amountInWithFee);

　　amountOut=numerator/denominator;

　　}