ERC-20

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ERC-20
Introduction
This tutorial helps you to create an example ERC-20 compatible token that conforms to the Klaytn Token Standards, especially Fungible Token Standard (ERC-20).
​ERC-20 Token Standard defines two events and 9 methods (including 3 optional methods) as below. ERC-20-compatible tokens are token contracts that implements the following interface.
function name() public view returns (string) //optional
function symbol() public view returns (string) //optional
function decimals() public view returns (uint8) //optional
function totalSupply() public view returns (uint256)
function balanceOf(address _owner) public view returns (uint256 balance)
function transfer(address _to, uint256 _value) public returns (bool success)
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success)
function approve(address _spender, uint256 _value) public returns (bool success)
function allowance(address _owner, address _spender) public view returns (uint256 remaining)
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event Transfer(address indexed _from, address indexed _to, uint256 _value)
event Approval(address indexed _owner, address indexed _spender, uint256 _value)
Based on above interface, developers may customize tokens by adding new features and logics, and deploy on Klaytn network. For more information, refer to official ERC-20 documentation.
In this tutorial, you are going to implement MyERC20.sol, an ERC-20 compatible token. This token will issue a predefined amount of tokens and sends all of the tokens to the contract owner on its deploy.
MyERC20.sol is based on OpenZeppelin's ERC20 implementation. A major part of the code in this tutorial is forked from OpenZeppelin 2.3  and following Solidity files are used to implement MyERC20.sol.
​https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v2.3.0/contracts/token/ERC20/IERC20.sol​
​https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v2.3.0/contracts/token/ERC20/ERC20.sol​
​https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v2.3.0/contracts/token/ERC20/ERC20Detailed.sol​
​https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v2.3.0/contracts/math/SafeMath.sol​
The rest of this tutorial is organized as follows.
​1. Writing ERC-20 smart contract​
1.1 Overall structure of MyERC20 code with whole MyERC20 code
1.2 Take a look at important functions
​2. Deploying smart contract​
2.1 Deploying smart contract using Klaytn IDE
2.2 Deploying smart contract using truffle
​3. Interacting between ERC-20 token and Klaytn wallet​
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1. Writing ERC-20 Smart Contract
Last modified 1yr ago
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