pragma solidity ^0.4.24;

contract ERC20Token {

      string public name = "DemoICO";
      string public symbol = "DICO";
      uint8 public decimals = 0;
      uint public INITIAL_SUPPLY = 10000 * (uint256(10) ** decimals);

      constructor() public {
          _mint(msg.sender, INITIAL_SUPPLY);
      }

      event Transfer(
        address indexed from,
        address indexed to,
        uint256 value
      );

      event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
      );

      using SafeMath for uint256;
      mapping (address => uint256) private _balances;
      mapping (address => mapping (address => uint256)) private _allowed;
      uint256 private _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);
      }

      function _mint(address account, uint256 value) internal {
        require(account != 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 != 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);
      }

}

library SafeMath {
      function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
          return 0;
        }
        uint256 c = a * b;
        require(c / a == b);
        return c;
      }
      function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0);
        uint256 c = a / b;
        return c;
      }
      function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;
        return c;
      }
      function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);
        return c;
      }
      function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
      }
}