ERC-20.sol

pragma solidity ^0.5.7;

interface ERC20 {
  function totalSupply() external view returns (uint256);
  
  function balanceOf(address who) external view returns (uint256);
  function transfer(address to, uint256 value) external returns (bool);
  
  function approve(address spender, uint256 value) external returns (bool);
  function allowance(address owner, address spender) external view returns (uint256);
  function transferFrom(address from, address to, uint256 value) external returns (bool);

  event Transfer(address indexed from, address indexed to, uint256 value);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}