ERC20Token.sol

pragma solidity ^0.5.0;
import "./SafeMath.sol";

contract ERC20 {
  using SafeMath for uint256;
  
  string public name;
  string public symbol;
  uint8 public decimals;

  mapping (address => uint256) private _balances;
  mapping (address => mapping (address => uint256)) private _allowed;

  uint256 private _totalSupply;
  
  event Transfer(address indexed _from, address indexed _to, uint256 _value);
  event Approval(address indexed _owner, address indexed _spender, uint256 _value);
  
  constructor() public{
      name = "MyToken888";
      symbol="MT8";
      decimals = 18;
      _mint(msg.sender,100000 * (10**18));
  }
  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 _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);
  }
  
  function _mint(address account, uint256 value) internal {
    require(account != address(0));
    _totalSupply = _totalSupply.add(value);
    _balances[account] = _balances[account].add(value);
    emit Transfer(address(0), account, value);
  }

  function _burn(address account, uint256 value) internal {
    require(account != address(0));
    require(value <= _balances[account]);

    _totalSupply = _totalSupply.sub(value);
    _balances[account] = _balances[account].sub(value);
    emit Transfer(account, address(0), value);
  }

  function _burnFrom(address account, uint256 value) internal {
    require(value <= _allowed[account][msg.sender]);
    
    _allowed[account][msg.sender] = _allowed[account][msg.sender].sub(value);
    _burn(account, value);
  }

}