#コード
これはERC20トークンをデプロイするためのサンプルコードです。
このスマートコントラクトはIERC20をExtendします。SafeMathをつかいます。
JPToken.sol
pragma solidity ^0.4.24;
import "https://github.com/OpenZeppelin/openzeppelin-solidity/contracts/token/ERC20/IERC20.sol";
import "https://github.com/OpenZeppelin/openzeppelin-solidity/contracts/math/SafeMath.sol";
contract JPToken is IERC20 {
using SafeMath for uint;
string public name;
string public symbol;
uint8 public decimals;
uint256 private _totalSupply;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowed;
constructor() public {
name = "James";
symbol = "JPS";
decimals = 18;
_totalSupply = 5000;
_balances[msg.sender] = _totalSupply;
}
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
function balanceOf(address owner) public view returns (uint256) {
return _balances[owner];
}
function allowance(
address owner,
address spender
)
public
view
returns (uint256)
{
return _allowed[owner][spender];
}
function transfer(address to, uint256 value) public returns (bool) {
_transfer(msg.sender, to, value);
return true;
}
function approve(address spender, uint256 value) public returns (bool) {
require(spender != address(0));
_allowed[msg.sender][spender] = value;
emit Approval(msg.sender, spender, value);
return true;
}
function transferFrom(
address from,
address to,
uint256 value
)
public
returns (bool)
{
require(value <= _allowed[from][msg.sender]);
_allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
_transfer(from, to, value);
return true;
}
function increaseAllowance(
address spender,
uint256 addedValue
)
public
returns (bool)
{
require(spender != address(0));
_allowed[msg.sender][spender] = (
_allowed[msg.sender][spender].add(addedValue));
emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
return true;
}
function decreaseAllowance(
address spender,
uint256 subtractedValue
)
public
returns (bool)
{
require(spender != address(0));
_allowed[msg.sender][spender] = (
_allowed[msg.sender][spender].sub(subtractedValue));
emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
return true;
}
function _transfer(address from, address to, uint256 value) internal {
require(value <= _balances[from]);
require(to != address(0));
_balances[from] = _balances[from].sub(value);
_balances[to] = _balances[to].add(value);
emit Transfer(from, to, value);
}
}
##Constructor
constructor() public {
name = "James";
symbol = "JPS";
decimals = 18;
_totalSupply = 5000;
_balances[msg.sender] = _totalSupply;
}
###Functions
使用しあたfunctionsです。トークンの合計金額を返します。トークンバランスを取得するアドレスを返します。
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
function balanceOf(address owner) public view returns (uint256) {
return _balances[owner];
}
function allowance(
address owner,
address spender
)
public
view
returns (uint256)
{
return _allowed[owner][spender];
}
function transfer(address to, uint256 value) public returns (bool) {
_transfer(msg.sender, to, value);
return true;
}
function approve(address spender, uint256 value) public returns (bool) {
require(spender != address(0));
_allowed[msg.sender][spender] = value;
emit Approval(msg.sender, spender, value);
return true;
}
function transferFrom(
address from,
address to,
uint256 value
)
public
returns (bool)
{
require(value <= _allowed[from][msg.sender]);
_allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
_transfer(from, to, value);
return true;
}
function increaseAllowance(
address spender,
uint256 addedValue
)
public
returns (bool)
{
require(spender != address(0));
_allowed[msg.sender][spender] = (
_allowed[msg.sender][spender].add(addedValue));
emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
return true;
}
function decreaseAllowance(
address spender,
uint256 subtractedValue
)
public
returns (bool)
{
require(spender != address(0));
_allowed[msg.sender][spender] = (
_allowed[msg.sender][spender].sub(subtractedValue));
emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
return true;
}
function _transfer(address from, address to, uint256 value) internal {
require(value <= _balances[from]);
require(to != address(0));
_balances[from] = _balances[from].sub(value);
_balances[to] = _balances[to].add(value);
emit Transfer(from, to, value);
}
}
ありがとうございます。
Link:
https://remix.ethereum.org/#optimize=true&version=soljson-v0.4.25+commit.59dbf8f1.js
ソース:
https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC20/ERC20.sol