Multiple users on the blockchain can jointly participate in the development of smart contracts,and the rights and obligations of both parties are clearly defined in the contract agreement.After both parties agree on the content and objectives of the contract,By developers converting these protocols into code,the code contains conditions that trigger automatic contract execution.

　　當(dāng)編碼完成后，智能合約就會被上傳到區(qū)塊鏈上，即全網(wǎng)驗(yàn)證節(jié)點(diǎn)都會接收這份合約信息。

　　區(qū)塊鏈等技術(shù)的參與。區(qū)塊鏈?zhǔn)荳eb3.0最突出的關(guān)鍵技術(shù)，助力安全、透明和防篡改的交易。Web3.0同時也包含其他機(jī)制促進(jìn)和推動去中心化，如云計(jì)算、AR Cloud和其他網(wǎng)絡(luò)空間關(guān)鍵技術(shù)等；

　　constructor(){

　　owner=msg.sender;

　　emit OwnerChanged(address(0),msg.sender);

　　feeAmountTickSpacing[500]=10;

　　emit FeeAmountEnabled(500,10);

　　feeAmountTickSpacing[3000]=60;

　　emit FeeAmountEnabled(3000,60);

　　feeAmountTickSpacing[10000]=200;

　　emit FeeAmountEnabled(10000,200);

　　}/// inheritdoc IUniswapV3Factory

　　function createPool(

　　address tokenA,

　　address tokenB,

　　uint24 fee

　　)external override noDelegateCall returns(address pool){

　　require(tokenA!=tokenB);

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

　　require(token0!=address(0));

　　int24 tickSpacing=feeAmountTickSpacing[fee];

　　require(tickSpacing!=0);

　　require(getPool[token0][token1][fee]==address(0));

　　pool=deploy(address(this),token0,token1,fee,tickSpacing);

　　getPool[token0][token1][fee]=pool;

　　//populate mapping in the reverse direction,deliberate choice to avoid the cost of comparing addresses

　　getPool[token1][token0][fee]=pool;

　　emit PoolCreated(token0,token1,fee,tickSpacing,pool);

　　}