// Vulnerability label: ARTHM
pragma solidity ^0.4.26;

contract ERC20Token {
	mapping (address => uint256) balances;
	address public owner;
    string public name;
    string public symbol;
    uint8 public decimals = 18;
	// total amount of tokens
    uint256 public totalSupply;
	// `allowed` tracks any extra transfer rights as in all ERC20 tokens
    mapping (address => mapping (address => uint256)) allowed;

    constructor() public {
        uint256 initialSupply = 10000000000;
        totalSupply = initialSupply * 10 ** uint256(decimals);
        balances[msg.sender] = totalSupply;
        name = "Game Chain";
        symbol = "GMI";
    }
	
    /// @param _owner The address from which the balance will be retrieved
    /// @return The balance
    function balanceOf(address _owner) public constant returns (uint256 balance) {
		 return balances[_owner];
	}

    /// @notice send `_value` token to `_to` from `msg.sender`
    /// @param _to The address of the recipient
    /// @param _value The amount of token to be transferred
    /// @return Whether the transfer was successful or not
    function transfer(address _to, uint256 _value) public returns (bool success) {
	    require(_value > 0 );                                      // Check send token value > 0;
		require(balances[msg.sender] >= _value);                   // Check if the sender has enough
        require(balances[_to] + _value > balances[_to]);           // Check for overflows											
		balances[msg.sender] -= _value;                            // Subtract from the sender
		balances[_to] += _value;                                   // Add the same to the recipient                       
		 
		emit Transfer(msg.sender, _to, _value); 			       // Notify anyone listening that this transfer took place
		return true;      
	}

    /// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
    /// @param _from The address of the sender
    /// @param _to The address of the recipient
    /// @param _value The amount of token to be transferred
    /// @return Whether the transfer was successful or not
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
	  
	    require(balances[_from] >= _value);                 // Check if the sender has enough
        require(balances[_to] + _value >= balances[_to]);   // Check for overflows
        require(_value <= allowed[_from][msg.sender]);      // Check allowance
        balances[_from] -= _value;                         // Subtract from the sender
        balances[_to] += _value;                           // Add the same to the recipient
        allowed[_from][msg.sender] -= _value;
        emit Transfer(_from, _to, _value);
        return true;
	}

    /// @notice `msg.sender` approves `_spender` to spend `_value` tokens
    /// @param _spender The address of the account able to transfer the tokens
    /// @param _value The amount of tokens to be approved for transfer
    /// @return Whether the approval was successful or not
    function approve(address _spender, uint256 _value) public returns (bool success) {
		require(balances[msg.sender] >= _value);
		allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
		return true;
	
	}
	
    /// @param _owner The address of the account owning tokens
    /// @param _spender The address of the account able to transfer the tokens
    /// @return Amount of remaining tokens allowed to spent
    function allowance(address _owner, address _spender) public constant returns (uint256 remaining) {
        return allowed[_owner][_spender];
	}
	
	/* This unnamed function is called whenever someone tries to send ether to it */
    function () private {
        revert();     // Prevents accidental sending of ether
    }

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}