HackTemp.sol

pragma solidity ^0.4.11;

import './IERC20.sol';
import './SafeMath.sol';

contract ReviewCoin is IERC20 {
    
    using SafeMath for uint256;
    uint public _totalSupply = 0;
    string public constant symbol = "REVIEW";
    string public name = "REVIEW COIN";
    uint8 public constant decimals = 18;
    
    // 1 ether will equal 500 SRBNT
    uint256 public constant RATE = 100;
    address public owner;
    
    mapping(address => uint) balances;
    mapping(address => mapping(address => uint)) allowed;
    
    function () payable{
        createTokens();
    }
    function ReviewCoin() {
        // balances[msg.sender] = _totalSupply;
        owner = msg.sender;
    } 
    
    function createTokens() payable {
        require(msg.value == 0);
        // uint256 tokens = RATE;
        uint256 tokens = 100;
        balances[msg.sender] = balances[msg.sender].add(tokens);
        _totalSupply = _totalSupply.add(tokens);
        owner.transfer(msg.value);
    }
    
    function totalSupply() constant returns (uint256 totalsupply){
        return _totalSupply;
    }
    
    function balanceOf(address _owner) constant returns (uint256 balance){
        return balances[_owner];
    }
    
    function transfer(address _to, uint256 _value) returns (bool success){
        require(
                 balances[msg.sender] >= _value
                 && _value > 0
            );
            balances[msg.sender] = balances[msg.sender].sub(_value);
            balances[_to] = balances[msg.sender].add(_value);
            Transfer(msg.sender, _to, _value);
            return true;
    } 
    
    function transferFrom(address _from, address _to, uint256 _value) returns (bool success){
        require(
            allowed[_from][msg.sender] > _value
            && balances[_from] >= _value
            && _value > 0
        );
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        Transfer(_from, _to, _value);
        return true;
    }
    
    function approve(address _spender, uint256 _value) returns (bool success){
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }
    
    function allowance(address _owner, address _spender) constant returns (uint256 remaining){
        return allowed[_owner][_spender];
    }
    
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}