The blockchain mall creates a perfect integration platform of consumer shopping and blockchain technology,so that the advantages of blockchain technology can serve the actual transaction scenario of consumer shopping and help consumers realize the dream of value-added shopping.The model first uses the blockchain mall platform to leverage the trend 系统-176搭建-0206+可电可 blockchain technology to help physical enterprises rapidly increase product sales,and at the same time,it also allows consumers to obtain substantial benefits in shopping.
pragma solidity>=0.5.0;
import'uniswap/v2-core/contracts/interfaces/IUniswapV2Pair.sol';
import"./SafeMath.sol";
library UniswapV2Library{
using SafeMath for uint;
//returns sorted token addresses,used to handle return values from pairs sorted in this order
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');
}
//calculates the CREATE2 address for a pair without making any external calls
// 在不进行任何外部调用的情况下计算一对的 CREATE2 地址
function pairFor(address factory,address tokenA,address tokenB)internal pure returns(address pair){
(address token0,address token1)=sortTokens(tokenA,tokenB);
