The important basis for the existence and development of the "new retail" business model is precisely the gradual improvement of people's requirements for personalization, immediacy, convenience, interactivity, accuracy and fragmentation in the shopping process. To meet the above needs, it depends on the "intelligent" shopping method to a certain extent. 新零售概念是什么?新零售，即企業(yè)依靠互聯(lián)網(wǎng)，利用大數(shù)據(jù)、人工智能等先進(jìn)技術(shù)，升級商品的生產(chǎn)、流通和銷售流程，進(jìn)而重塑商業(yè)結(jié)構(gòu)和生態(tài)圈，是一種新的零售模式，它將線上服務(wù)、線下經(jīng)驗(yàn)和現(xiàn)代物流緊密結(jié)合在一起。 　　//SPDX-License-Identifier:MIT 　　pragma solidity^0.6.0; 　　library SafeMath{ 　　function add(uint256 a,uint256 b)internal pure returns(uint256){開發(fā)原理I35源碼7o98模式o7I8 　　uint256 c=a+b; 　　require(c>=a,"SafeMath:addition overflow"); 　　return c; 　　} 　　function sub(uint256 a,uint256 b)internal pure returns(uint256){ 　　return sub(a,b,"SafeMath:subtraction overflow"); 　　} 　　function sub(uint256 a,uint256 b,string memory errorMessage)internal pure returns(uint256){ 　　require(b<=a,errorMessage);詳細(xì)案例及技術(shù)：mrsfu123 　　uint256 c=a-b; 　　return c; 　　} 　　function mul(uint256 a,uint256 b)internal pure returns(uint256){ 　　if(a==0){ 　　return 0; 　　} 　　uint256 c=a*b; 　　require(c/a==b,"SafeMath:multiplication overflow"); 　　return c; 　　} 　　function div(uint256 a,uint256 b)internal pure returns(uint256){ 　　return div(a,b,"SafeMath:division by zero"); 　　} 　　function div(uint256 a,uint256 b,string memory errorMessage)internal pure returns(uint256){ 　　require(b>0,errorMessage); 　　uint256 c=a/b; 　　//assert(a==b*c+a%b);//There is no case in which this doesn't hold 　　return c; 　　} 　　function mod(uint256 a,uint256 b)internal pure returns(uint256){ 　　return mod(a,b,"SafeMath:modulo by zero"); 　　} 　　function mod(uint256 a,uint256 b,string memory errorMessage)internal pure returns(uint256){ 　　require(b!=0,errorMessage); 　　return a%b; 　　} 　　} 　　interface IERC20{ 　　function totalSupply()external view returns(uint256); 　　function balanceOf(address account)external view returns(uint256); 　　function transfer(address recipient,uint256 amount)external returns(bool); 　　function allowance(address owner,address spender)external view returns(uint256); 　　function approve(address spender,uint256 amount)external returns(bool); 　　function transferFrom(address sender,address recipient,uint256 amount)external returns(bool); 　　event Transfer(address indexed from,address indexed to,uint256 value); 　　event Approval(address indexed owner,address indexed