interface IERC20 {
    function totalSupply() constant returns (uint256 totalSupply);
    function balanceOf(address _owner) constant returns (uint256 balance);
    function transfer(address _to, uint256 _value) returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
    function approve(address _spender, uint256 _value) returns (bool success);
    function allowance(address _owner, address _spender) constant returns (uint256 remaining);
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}

contract IGoldToken is IERC20 {
    uint public constant _totalSupply = 500000000000000;
    string public constant symbol = "IGP";
    string public constant name = "IGoldPro";
    uint8 public constant decimals = 8;
    
    
    mapping(address => uint256) balances;
    mapping(address=> mapping(address=> uint256)) allowed;
    function IGoldToken(){
        balances[msg.sender] = _totalSupply;
    }
    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] -= _value;
        balances[_to] += _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] -= _value;
        balances[_to] += _value;
        allowed[_from][msg.sender] =- _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);
}