DApp是指基于區(qū)塊鏈技術(shù)的去中心化應(yīng)用程序，它的特點(diǎn)是去中心化、透明、安全、不可篡改等，DApp is an inevitable trend because it can solve problems such as centralization,data privacy,and security in traditional applications,while also achieving more fair,transparent,and decentralized application scenarios.

　　DApp和APP的最大不同在于，DApp是基于區(qū)塊練技術(shù)的去中心化應(yīng)用程序，而APP是基于中心化服務(wù)器的應(yīng)用程序，The data storage and processing of DApp are distributed,without centralized servers,so it has higher security and reliability.

　　function addLiquidity(

　　address tokenA,

　　address tokenB,

　　uint amountADesired,

　　uint amountBDesired,

　　uint amountAMin,

　　uint amountBMin,

　　address to,

　　uint deadline

　　)external returns(uint amountA,uint amountB,uint liquidity);

　　if(IUniswapV2Factory(factory).getPair(tokenA,tokenB)==address(0)){

　　IUniswapV2Factory(factory).createPair(tokenA,tokenB);

　　}

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

　　hex'ff',

　　factory,

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

　　hex'96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f'//init code hash

　　))));

　　function removeLiquidity(

　　address tokenA,

　　address tokenB,

　　uint liquidity,

　　uint amountAMin,

　　uint amountBMin,

　　address to,

　　uint deadline

　　)external returns(uint amountA,uint amountB);