星云激励计划-每提交一个有效DApp即可获得100 NAS

星云激励计划-每提交一个有效DApp即可获得100 NAS https://incentive.nebulas.io/cn/signup.html?invite=zbuIr

 

配套教程:

手把手教你星云DApp开发(第二部分)

https://mp.weixin.qq.com/s/2ZrKnOoWyNxMUyy2OUlpiA

手把手教你星云DApp开发(第一部分)

https://mp.weixin.qq.com/s?__biz=MzU2MTI5OTI3MA==&mid=2247484586&idx=2&sn=c0cd24f74a8527a7fd07391b758a4bf8&chksm=fc7bae83cb0c2795e82e1bbba1f083f6bfd1650dea46cf130265c3e86ad5d3acb22d035e768a&scene=21#wechat_redirect

dapp 开发:10 分钟 5 步发布以太坊 ERC20 代币

1.安装 METAMASK

Brings Ethereum to your browser

一个可以浏览器上进行操作的以太坊钱包,推荐 Chrome。

Chrome 插件安装地址:

https://chrome.google.com/webstore/detail/metamask/nkbihfbeogaeaoehlefnkodbefgpgknn​chrome.google.com

2.在 METAMASK 创建钱包

 

3.从以太坊官网复制代币代码模板

Create a cryptocurrency contract in Ethereum​www.ethereum.org

https://www.ethereum.org/token

从以太坊官网复制的代码模板

pragma solidity ^0.4.16;

interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external; }

contract TokenERC20 {
    // Public variables of the token
    string public name;
    string public symbol;
    uint8 public decimals = 18;
    // 18 decimals is the strongly suggested default, avoid changing it
    uint256 public totalSupply;

    // This creates an array with all balances
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    // This generates a public event on the blockchain that will notify clients
    event Transfer(address indexed from, address indexed to, uint256 value);

    // This notifies clients about the amount burnt
    event Burn(address indexed from, uint256 value);

    /**
     * Constructor function
     *
     * Initializes contract with initial supply tokens to the creator of the contract
     */
    function TokenERC20(
        uint256 initialSupply,
        string tokenName,
        string tokenSymbol
    ) public {
        totalSupply = initialSupply * 10 ** uint256(decimals);  // Update total supply with the decimal amount
        balanceOf[msg.sender] = totalSupply;                // Give the creator all initial tokens
        name = tokenName;                                   // Set the name for display purposes
        symbol = tokenSymbol;                               // Set the symbol for display purposes
    }

    /**
     * Internal transfer, only can be called by this contract
     */
    function _transfer(address _from, address _to, uint _value) internal {
        // Prevent transfer to 0x0 address. Use burn() instead
        require(_to != 0x0);
        // Check if the sender has enough
        require(balanceOf[_from] >= _value);
        // Check for overflows
        require(balanceOf[_to] + _value >= balanceOf[_to]);
        // Save this for an assertion in the future
        uint previousBalances = balanceOf[_from] + balanceOf[_to];
        // Subtract from the sender
        balanceOf[_from] -= _value;
        // Add the same to the recipient
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
        // Asserts are used to use static analysis to find bugs in your code. They should never fail
        assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
    }

    /**
     * Transfer tokens
     *
     * Send `_value` tokens to `_to` from your account
     *
     * @param _to The address of the recipient
     * @param _value the amount to send
     */
    function transfer(address _to, uint256 _value) public {
        _transfer(msg.sender, _to, _value);
    }

    /**
     * Transfer tokens from other address
     *
     * Send `_value` tokens to `_to` on behalf of `_from`
     *
     * @param _from The address of the sender
     * @param _to The address of the recipient
     * @param _value the amount to send
     */
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(_value <= allowance[_from][msg.sender]);     // Check allowance
        allowance[_from][msg.sender] -= _value;
        _transfer(_from, _to, _value);
        return true;
    }

    /**
     * Set allowance for other address
     *
     * Allows `_spender` to spend no more than `_value` tokens on your behalf
     *
     * @param _spender The address authorized to spend
     * @param _value the max amount they can spend
     */
    function approve(address _spender, uint256 _value) public
        returns (bool success) {
        allowance[msg.sender][_spender] = _value;
        return true;
    }

    /**
     * Set allowance for other address and notify
     *
     * Allows `_spender` to spend no more than `_value` tokens on your behalf, and then ping the contract about it
     *
     * @param _spender The address authorized to spend
     * @param _value the max amount they can spend
     * @param _extraData some extra information to send to the approved contract
     */
    function approveAndCall(address _spender, uint256 _value, bytes _extraData)
        public
        returns (bool success) {
        tokenRecipient spender = tokenRecipient(_spender);
        if (approve(_spender, _value)) {
            spender.receiveApproval(msg.sender, _value, this, _extraData);
            return true;
        }
    }

    /**
     * Destroy tokens
     *
     * Remove `_value` tokens from the system irreversibly
     *
     * @param _value the amount of money to burn
     */
    function burn(uint256 _value) public returns (bool success) {
        require(balanceOf[msg.sender] >= _value);   // Check if the sender has enough
        balanceOf[msg.sender] -= _value;            // Subtract from the sender
        totalSupply -= _value;                      // Updates totalSupply
        emit Burn(msg.sender, _value);
        return true;
    }

    /**
     * Destroy tokens from other account
     *
     * Remove `_value` tokens from the system irreversibly on behalf of `_from`.
     *
     * @param _from the address of the sender
     * @param _value the amount of money to burn
     */
    function burnFrom(address _from, uint256 _value) public returns (bool success) {
        require(balanceOf[_from] >= _value);                // Check if the targeted balance is enough
        require(_value <= allowance[_from][msg.sender]);    // Check allowance
        balanceOf[_from] -= _value;                         // Subtract from the targeted balance
        allowance[_from][msg.sender] -= _value;             // Subtract from the sender's allowance
        totalSupply -= _value;                              // Update totalSupply
        emit Burn(_from, _value);
        return true;
    }
}

4.修改代币参数

主要是修改名称,如截图所示,修改为你的代币名称。

5.发布到以太坊网络

以太坊在线开发环境,可以自动连接到 METAMASK。

https://remix.ethereum.orgRemix – Solidity IDERemix – Solidity IDE

https://remix.ethereum.org/

如果你的以太坊账号上已经有余额的话,就可以直接进行部署了。

 

发布之后可以在 METAMASK 直接看到自己刚发布的代币:

AICoin 是为了促进人工智能社区发展诞生的代币,代币的主要用途是奖励人工智能开发者分享数据和模型。

英文名:AICoin

中文名:人工智能币

简称:AIC

总量:100000000.000AIC

技术合作微信:fendouai,注明:DAPP

DAPP开发,区块链开发群号:374475398

DAPP 总群,加微信,发送:dapp 自动拉入微信总群

 

以太坊电商DApp实战

本课程面向有一定基础的以太坊DApp开发者,通过一个去中心化电商DApp的完整开发过程,引导学习者在实战中深入理解并掌握如何基于以太坊开发去中心化应用。课程涵盖以太坊、IPFS、MongDB、Express等诸多技术点,采用敏捷开发思路,内容深入浅出,是不可多得的以太坊DApp实战课程。

http://xc.hubwiz.com/course/5abbb7acc02e6b6a59171dd6/?affid=wmqlogdown

以太坊DApp开发入门

本课程面向初学者,内容涵盖以太坊去中心化应用开发相关的诸多概念,如区块链、ganache仿真器、Solidity语言、solc编译器、web3js库、通证(代币)发行等,并将手把手地教大家如何构建一个基于以太坊的完整去中心化应用 —— 区块链投票系统。

http://xc.hubwiz.com/course/5a952991adb3847553d205d1?affid=wmqlogdown

DApp-去中心化应用

去中心化应用也被称为DApp(decentralized applications),是技术进化的下一个合乎逻辑的步骤。一个去中心化应用,类似以太坊上的智能合约,但也有关键不同。不像智能合约,DApp不需仅围绕金融,还可将区块链技术用于可想到的任何用途。
大多数人都知道,一个智能合约是基于区块链的,一个两方或更多方之间的去中心化互信纽带(bond)。智能合约(以目前2017年早期形式来看)的运转需要一个金融激励,并对任何给定时间的参与人数提出一些限制。去中心化应用或DApps,可对这项技术作出相当大幅度的改进。
DApp技术的主要卖点之一,是其可容纳市场各方无限数量的参与者。此外,DApp 可将区块链技术用于其他用途,而不仅仅是一个金融产出。在我们此篇文章,我们列出了DApp的可能用例。
当要创建一个新的DApp,了解这项技术,要比编写智能合约容易一点。不要误解为任何人都可突然凭空创建一个DApp,只是其学习曲线不是那么陡峭。感兴趣的人应该去 Google 搜索创建一个新 DApp 的方法,将可以立即起步。
DApp 有两个主要类别。完全匿名的DApp 允许每一个参与者可保持一级匿名,所有互动的发生都是自动和即时。这项技术的知名主流案例是 BitTorrent ,流行的点对点传输协议。
另一类是基于声誉的DApp,在这个生态系统中,节点被跟踪,并维护应用内部状态(nodes are tracked and maintain status inside the applications)。确保信任度,是这个基于声誉的DApp世界中,最重要的事。但是,还没有办法,将一个货币价值附于一个人的信任等级之上,也不能将其信任等级(it)转移给其他任何人(However, there is no way to attach a monetary value to one’s trust level, nor can it be transferred to anyone else.)。
一些人可能想知道,比如 Bitcoin 这样的概念,在DApp世界中处于什么样的位置。很有趣,比特币处于以上两个类别之间。不能将比特币限定为一个传统应用,因为其虚拟财产在生态系统内部拥有价值。
很明显,所有种类的DApp前进之路上,还有大量空间,DApp生态系统接下来将会显著扩展。
原文:https://themerkle.com/what-is-a-dapp/
作者:JP Buntinx
编译:子文@币未来 biweilai.com