Comisiones porcentuales

percentual_tax.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.6;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/release-v4.3/contracts/token/ERC20/ERC20.sol";

contract MyERC20 is ERC20 {
  string TOKEN_NAME = "Token";
  string TOKEN_SYMBOL = "TKN";
  uint256 TOTAL_SUPPLY = 21000000 ether;
  address LIQUIDITY_ADDRESS = 0x0000000000000000000000000000000000000000;
  address MARKETING_ADDRESS = 0x0000000000000000000000000000000000000000;
  uint256 LIQUIDITY_TX_PERCENTAGE_FEE = 700; // 700 = 7,00%
  uint256 MARKETING_TX_PERCENTAGE_FEE = 500; // 500 = 5,00%
  
  constructor () ERC20(TOKEN_NAME, TOKEN_SYMBOL) {
    _mint(msg.sender, TOTAL_SUPPLY);
  }
  
  function getPercentage(uint256 number, uint256 percentage) internal pure returns(uint256 result)
  {
    return number * percentage / 10000;
  }
  
  function _afterTokenTransfer(address from, address to, uint256 amount) internal override
  {
    if(from != address(0) && to != address(0))
    {
      uint256 liquidity_amount = getPercentage(amount, LIQUIDITY_TX_PERCENTAGE_FEE);
      uint256 marketing_amount = getPercentage(amount, MARKETING_TX_PERCENTAGE_FEE);
      
      _mint(LIQUIDITY_ADDRESS, liquidity_amount);
      _mint(MARKETING_ADDRESS, marketing_amount);
      
      _burn(to, liquidity_amount);
      _burn(to, marketing_amount);
    }
  }
}