ECTSToken Solidity Contract

ECTSToken.sol

//lock to 0.4.18 <= compiler version < 0.5
pragma solidity^0.4.18;

import "./ERC20.sol";

contract ECTSToken is ERC20 {
    string public constant name = 'ECTS Token';
    string public constant symbol = 'ECTS';
    uint8 public constant decimals = 0;
    uint256 public totalSupply = 0;

    address public owner;

    mapping (address => mapping (address => uint256)) allowed;
    mapping (address => uint256) public balanceOf;

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    function ECTSToken() public {
        owner = msg.sender;
        balanceOf[owner] = totalSupply;
    }

    function totalSupply() constant public returns (uint256 _totalSupply) {
        _totalSupply = totalSupply;
    }

    function balanceOf(address _owner) constant public returns (uint256 balance) {
        return balanceOf[_owner];
    }

    function approve(address _spender, uint256 _value) public returns (bool success) {
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        success = true;
    }

    function allowance(address _owner, address _spender) constant public returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(_to != 0x0);
        require(balanceOf[_from] >= _value);
        require(balanceOf[_to] + _value >= balanceOf[_to]);
        require(allowed[_from][msg.sender] >= _value);
        balanceOf[_to] +=_value;
        balanceOf[_from] -= _value;
        allowed[_from][msg.sender] -= _value;
        Transfer(_from, _to, _value);
        success = true;
    }

    function transfer(address _to, uint256 _value) public returns (bool success) {
        require(balanceOf[msg.sender] > _value);
        require(balanceOf[_to] + _value > balanceOf[_to]);
        balanceOf[msg.sender] -= _value;
        balanceOf[_to] += _value;
        success = true;
    }

    function mintTokens(uint256 _tokens) public onlyOwner {
        totalSupply += _tokens;
        balanceOf[owner] += _tokens;
    }

}