i got problem - Githubissues

as required exceeds limit: 3000000. An important gas estimation might also be the sign of a problem in the contract code. Please check loops and be sure you did not sent value to a non payable function (that's also the reason of strong gas estimation)

`pragma solidity ^0.4.11;

/**

@title SafeMath
@dev Math operations with safety checks that throw on error / library SafeMath { function mul(uint256 a, uint256 b) internal constant returns (uint256) { uint256 c = a b; assert(a == 0 || c / a == b); return c; }

function div(uint256 a, uint256 b) internal constant returns (uint256) { // assert(b > 0); // Solidity automatically throws when dividing by 0 uint256 c = a / b; // assert(a == b * c + a % b); // There is no case in which this doesn't hold return c; }

function sub(uint256 a, uint256 b) internal constant returns (uint256) { assert(b <= a); return a - b; }

function add(uint256 a, uint256 b) internal constant returns (uint256) { uint256 c = a + b; assert(c >= a); return c; } }

/**

@title Crowdsale
@dev Crowdsale is a base contract for managing a token crowdsale.
Crowdsales have a start and end timestamps, where investors can make
token purchases and the crowdsale will assign them tokens based
on a token per ETH rate. Funds collected are forwarded to a wallet
as they arrive. */ contract Crowdsale { using SafeMath for uint256;

// The token being sold MintableToken public token;

// start and end timestamps where investments are allowed (both inclusive) uint256 public startTime; uint256 public endTime;

// address where funds are collected address public wallet;

// how many token units a buyer gets per wei uint256 public rate;

// amount of raised money in wei uint256 public weiRaised;

/**
- event for token purchase logging
- @param purchaser who paid for the tokens
- @param beneficiary who got the tokens
- @param value weis paid for purchase
- @param amount amount of tokens purchased */ event TokenPurchase(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);
function Crowdsale(uint256 _startTime, uint256 _endTime, uint256 _rate, address _wallet) { require(_startTime >= now); require(_endTime >= _startTime); require(_rate > 0); require(_wallet != address(0));

token = createTokenContract(); startTime = _startTime; endTime = _endTime; rate = _rate; wallet = _wallet; }

// creates the token to be sold. // override this method to have crowdsale of a specific mintable token. function createTokenContract() internal returns (MintableToken) { return new MintableToken(); }

// fallback function can be used to buy tokens function () payable { buyTokens(msg.sender); }

// low level token purchase function function buyTokens(address beneficiary) public payable { require(beneficiary != address(0)); require(validPurchase());

uint256 weiAmount = msg.value;

// calculate token amount to be created uint256 tokens = weiAmount.mul(rate);

// update state weiRaised = weiRaised.add(weiAmount);

token.mint(beneficiary, tokens); TokenPurchase(msg.sender, beneficiary, weiAmount, tokens);

forwardFunds(); }

// send ether to the fund collection wallet // override to create custom fund forwarding mechanisms function forwardFunds() internal { wallet.transfer(msg.value); }

// @return true if the transaction can buy tokens function validPurchase() internal constant returns (bool) { bool withinPeriod = now >= startTime && now <= endTime; bool nonZeroPurchase = msg.value != 0; return withinPeriod && nonZeroPurchase; }

// @return true if crowdsale event has ended function hasEnded() public constant returns (bool) { return now > endTime; }

} /**

@title CappedCrowdsale
@dev Extension of Crowdsale with a max amount of funds raised */ contract CappedCrowdsale is Crowdsale { using SafeMath for uint256;

uint256 public cap;

function CappedCrowdsale(uint256 _cap) { require(_cap > 0); cap = _cap; }

// overriding Crowdsale#validPurchase to add extra cap logic // @return true if investors can buy at the moment function validPurchase() internal constant returns (bool) { bool withinCap = weiRaised.add(msg.value) <= cap; return super.validPurchase() && withinCap; }

// overriding Crowdsale#hasEnded to add cap logic // @return true if crowdsale event has ended function hasEnded() public constant returns (bool) { bool capReached = weiRaised >= cap; return super.hasEnded() || capReached; }

}

/**

@title Ownable
@dev The Ownable contract has an owner address, and provides basic authorization control
functions, this simplifies the implementation of "user permissions". */ contract Ownable { address public owner;

event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

/**
- @dev The Ownable constructor sets the original owner of the contract to the sender
- account. */ function Ownable() { owner = msg.sender; }
/**
- @dev Throws if called by any account other than the owner. */ modifier onlyOwner() { require(msg.sender == owner); _; }
/**
- @dev Allows the current owner to transfer control of the contract to a newOwner.
- @param newOwner The address to transfer ownership to. */ function transferOwnership(address newOwner) onlyOwner public { require(newOwner != address(0)); OwnershipTransferred(owner, newOwner); owner = newOwner; }

}

/**

@title FinalizableCrowdsale
@dev Extension of Crowdsale where an owner can do extra work
after finishing. */ contract FinalizableCrowdsale is Crowdsale, Ownable { using SafeMath for uint256;

bool public isFinalized = false;

event Finalized();

/**
- @dev Must be called after crowdsale ends, to do some extra finalization
- work. Calls the contract's finalization function. */ function finalize() onlyOwner public { require(!isFinalized); require(hasEnded());
finalization(); Finalized();

isFinalized = true; }

/**
- @dev Can be overridden to add finalization logic. The overriding function
- should call super.finalization() to ensure the chain of finalization is
- executed entirely. */ function finalization() internal { } }

/**

@title RefundVault
@dev This contract is used for storing funds while a crowdsale
is in progress. Supports refunding the money if crowdsale fails,
and forwarding it if crowdsale is successful. */ contract RefundVault is Ownable { using SafeMath for uint256;

enum State { Active, Refunding, Closed }

mapping (address => uint256) public deposited; address public wallet; State public state;

event Closed(); event RefundsEnabled(); event Refunded(address indexed beneficiary, uint256 weiAmount);

function RefundVault(address _wallet) { require(_wallet != 0x0); wallet = _wallet; state = State.Active; }

function deposit(address investor) onlyOwner public payable { require(state == State.Active); deposited[investor] = deposited[investor].add(msg.value); }

function close() onlyOwner public { require(state == State.Active); state = State.Closed; Closed(); wallet.transfer(this.balance); }

function enableRefunds() onlyOwner public { require(state == State.Active); state = State.Refunding; RefundsEnabled(); }

function refund(address investor) public { require(state == State.Refunding); uint256 depositedValue = deposited[investor]; deposited[investor] = 0; investor.transfer(depositedValue); Refunded(investor, depositedValue); } }

/**

@title RefundableCrowdsale
@dev Extension of Crowdsale contract that adds a funding goal, and
the possibility of users getting a refund if goal is not met.
Uses a RefundVault as the crowdsale's vault. */ contract RefundableCrowdsale is FinalizableCrowdsale { using SafeMath for uint256;

// minimum amount of funds to be raised in weis uint256 public goal;

// refund vault used to hold funds while crowdsale is running RefundVault public vault;

function RefundableCrowdsale(uint256 _goal) { require(_goal > 0); vault = new RefundVault(wallet); goal = _goal; }

// We're overriding the fund forwarding from Crowdsale. // In addition to sending the funds, we want to call // the RefundVault deposit function function forwardFunds() internal { vault.deposit.value(msg.value)(msg.sender); }

// if crowdsale is unsuccessful, investors can claim refunds here function claimRefund() public { require(isFinalized); require(!goalReached());

vault.refund(msg.sender); }

// vault finalization task, called when owner calls finalize() function finalization() internal { if (goalReached()) { vault.close(); } else { vault.enableRefunds(); }

super.finalization(); }

function goalReached() public constant returns (bool) { return weiRaised >= goal; }

}

/**

@title ERC20Basic
@dev Simpler version of ERC20 interface
@dev see https://github.com/ethereum/EIPs/issues/179 */ contract ERC20Basic { uint256 public totalSupply; function balanceOf(address who) public constant returns (uint256); function transfer(address to, uint256 value) public returns (bool); event Transfer(address indexed from, address indexed to, uint256 value); }

/**

@title Basic token
@dev Basic version of StandardToken, with no allowances. */ contract BasicToken is ERC20Basic { using SafeMath for uint256;

mapping(address => uint256) balances;

/**
- @dev transfer token for a specified address
- @param _to The address to transfer to.
- @param _value The amount to be transferred. */ function transfer(address _to, uint256 _value) public returns (bool) { require(_to != address(0)); require(_value <= balances[msg.sender]);
// SafeMath.sub will throw if there is not enough balance. balances[msg.sender] = balances[msg.sender].sub(_value); balances[_to] = balances[_to].add(_value); Transfer(msg.sender, _to, _value); return true; }

/**
- @dev Gets the balance of the specified address.
- @param _owner The address to query the the balance of.
- @return An uint256 representing the amount owned by the passed address. */ function balanceOf(address _owner) public constant returns (uint256 balance) { return balances[_owner]; }

}

/**

@title ERC20 interface
@dev see https://github.com/ethereum/EIPs/issues/20 */ contract ERC20 is ERC20Basic { function allowance(address owner, address spender) public constant returns (uint256); function transferFrom(address from, address to, uint256 value) public returns (bool); function approve(address spender, uint256 value) public returns (bool); event Approval(address indexed owner, address indexed spender, uint256 value); }

/**

@title Standard ERC20 token
@dev Implementation of the basic standard token.
@dev https://github.com/ethereum/EIPs/issues/20
@dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol */ contract StandardToken is ERC20, BasicToken {

mapping (address => mapping (address => uint256)) internal allowed;

/**
- @dev Transfer tokens from one address to another
- @param _from address The address which you want to send tokens from
- @param _to address The address which you want to transfer to
- @param _value uint256 the amount of tokens to be transferred */ function transferFrom(address _from, address _to, uint256 _value) public returns (bool) { require(_to != address(0)); require(_value <= balances[_from]); require(_value <= allowed[_from][msg.sender]);
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; }

/**
- @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
- Beware that changing an allowance with this method brings the risk that someone may use both the old
- and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
- race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
- https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
- @param _spender The address which will spend the funds.
- @param _value The amount of tokens to be spent. */ function approve(address _spender, uint256 _value) public returns (bool) { allowed[msg.sender][_spender] = _value; Approval(msg.sender, _spender, _value); return true; }
/**
- @dev Function to check the amount of tokens that an owner allowed to a spender.
- @param _owner address The address which owns the funds.
- @param _spender address The address which will spend the funds.
- @return A uint256 specifying the amount of tokens still available for the spender. */ function allowance(address _owner, address _spender) public constant returns (uint256 remaining) { return allowed[_owner][_spender]; }
/**
- approve should be called when allowed[_spender] == 0. To increment
- allowed value is better to use this function to avoid 2 calls (and wait until
- the first transaction is mined)
- From MonolithDAO Token.sol */ function increaseApproval (address _spender, uint _addedValue) public returns (bool success) { allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue); Approval(msg.sender, _spender, allowed[msg.sender][_spender]); return true; }
function decreaseApproval (address _spender, uint _subtractedValue) public returns (bool success) { uint oldValue = allowed[msg.sender][_spender]; if (_subtractedValue > oldValue) { allowed[msg.sender][_spender] = 0; } else { allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue); } Approval(msg.sender, _spender, allowed[msg.sender][_spender]); return true; }

}

/**

@title Mintable token
@dev Simple ERC20 Token example, with mintable token creation
@dev Issue: * https://github.com/OpenZeppelin/zeppelin-solidity/issues/120
Based on code by TokenMarketNet: https://github.com/TokenMarketNet/ico/blob/master/contracts/MintableToken.sol */

contract MintableToken is StandardToken, Ownable { event Mint(address indexed to, uint256 amount); event MintFinished();

bool public mintingFinished = false;

modifier canMint() { require(!mintingFinished); _; }

/**

@dev Function to mint tokens
@param _to The address that will receive the minted tokens.
@param _amount The amount of tokens to mint.
@return A boolean that indicates if the operation was successful. */ function mint(address _to, uint256 _amount) onlyOwner canMint public returns (bool) { totalSupply = totalSupply.add(_amount); balances[_to] = balances[_to].add(_amount); Mint(_to, _amount); Transfer(address(0), _to, _amount); return true; }

/**
@dev Function to stop minting new tokens.
@return True if the operation was successful. */ function finishMinting() onlyOwner public returns (bool) { mintingFinished = true; MintFinished(); return true; } }

/**

@title SampleCrowdsaleToken
@dev Very simple ERC20 Token that can be minted.
It is meant to be used in a crowdsale contract. */

contract SampleCrowdsaleToken is MintableToken {

string public constant name = "Sample Crowdsale Token"; string public constant symbol = "SCTV2"; uint8 public constant decimals = 18;

}

/**

@title SampleCrowdsale
@dev This is an example of a fully fledged crowdsale.
The way to add new features to a base crowdsale is by multiple inheritance.
In this example we are providing following extensions:
CappedCrowdsale - sets a max boundary for raised funds
RefundableCrowdsale - set a min goal to be reached and returns funds if it's not met
After adding multiple features it's good practice to run integration tests
to ensure that subcontracts works together as intended. */ contract SampleCrowdsale is CappedCrowdsale, RefundableCrowdsale {

function SampleCrowdsale(uint256 _startTime, uint256 _endTime, uint256 _rate, uint256 _goal, uint256 _cap, address _wallet) CappedCrowdsale(_cap) FinalizableCrowdsale() RefundableCrowdsale(_goal) Crowdsale(_startTime, _endTime, _rate, _wallet) { //As goal needs to be met for a successful crowdsale //the value needs to less or equal than a cap which is limit for accepted funds require(_goal <= _cap); }

function createTokenContract() internal returns (MintableToken) { return new SampleCrowdsaleToken(); }

OpenZeppelin / openzeppelin-contracts

i got problem #541