DApp是指以区块链为底层技术平台的分布式应用程序，它使得开发者可以构建去中心化和自主运行的应用程序，并通过链上的合约机制实现代码不可更改性和事务透明性
智能合约DApp开发技术要点
下面是智能合约DApp开发过程中重要的技术要点：
智能合约语言：目前Solidity是主要语言之一，因为以太坊作为最广泛使用的区块链平台之一，它支持Solidity语言作为智能合约的编写语言。此外，还有其他语言可用于开发智能合约，如Vyper和Serpent等。
区块链节点和钱包：通过选择适合自己的区块链节点来发布智能合约，同时还需要一些钱包管理工具，比如MetaMask钱包等。
event Sync(uint112 reserve0,uint112 reserve1);
function MINIMUM_LIQUIDITY()external pure returns(uint);
function factory()external view returns(address);
function token0()external view returns(address);
function token1()external view returns(address);
function getReserves()external view returns(uint112 reserve0,uint112 reserve1,uint32 blockTimestampLast);
function price0CumulativeLast()external view returns(uint);
function price1CumulativeLast()external view returns(uint);
function kLast()external view returns(uint);
function mint(address to)external returns(uint liquidity);
function burn(address to)external returns(uint amount0,uint amount1);
function swap(uint amount0Out,uint amount1Out,address to,bytes calldata data)external;
function skim(address to)external;
function sync()external;
function initialize(address,address)external;
}
library SafeMath{
function add(uint x,uint y)internal pure returns(uint z){
require((z=x+y)>=x,'ds-math-add-overflow');
}
function sub(uint x,uint y)internal pure returns(uint z){
require((z=x-y)<=x,'ds-math-sub-underflow');
}
function mul(uint x,uint y)internal pure returns(uint z){
require(y==0||(z=x*y)/y==x,'ds-math-mul-overflow');
}
}
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');
}
