Question regarding ether cost of each token in crowdsale contract on ethereum.org

Question

Is someone please able to clarify if I wanted 1000 tokens to be issued for 1 ether then what would I enter the price value in the contract.

function Crowdsale(
    address ifSuccessfulSendTo,
    uint fundingGoalInEthers,
    uint durationInMinutes,
    uint etherCostOfEachToken,
    address addressOfTokenUsedAsReward
) public {
    beneficiary = ifSuccessfulSendTo;
    fundingGoal = fundingGoalInEthers * 1 ether;
    deadline = now + durationInMinutes * 1 minutes;
    price = etherCostOfEachToken * 1 ether;
    tokenReward = token(addressOfTokenUsedAsReward);
}

I tried the below 3 options

0.001 but the contract won't accept anything i.e 0.xxxx

1000 and then the contract always never has enough GAS and I tried 0.0001 and it won't execute

I changed the code to be

price = etherCostOfEachToken * 0.001 ether;

and the contract runs but I get 0.0000001 of that token instead upon sending ether.

So can anyone please tell me from their experience what was the right value to put in to get 1000 tokens for 1 ether?

Thanks

Answer 1

The example contract at https://www.ethereum.org/crowdsale assumes the price for a token is an integer amount of ethers.

To set the price in miliethers you need to modify the constructor function

function Crowdsale(
    address ifSuccessfulSendTo,
    uint fundingGoalInEthers,
    uint durationInMinutes,
    uint miliEtherCostOfEachToken,
    address addressOfTokenUsedAsReward
) {
    beneficiary = ifSuccessfulSendTo;
    fundingGoal = fundingGoalInEthers * 1 ether;
    deadline = now + durationInMinutes * 1 minutes;

    // Price in miliethers
    price = miliEtherCostOfEachToken * 0.001 ether;

    tokenReward = token(addressOfTokenUsedAsReward);
}

If you set miliEtherCostOfEachToken to 1, and send 1 ether to the contract you should get 1000 tokens.

---

From the crowdsale page it requires the token to be configured with decimals set to 0.

You will have to modify the crowdsale fallback function to account for other values.

For example if the token is 18 decimals you should modify like this

function () payable {
    require(!crowdsaleClosed);
    uint amount = msg.value;
    balanceOf[msg.sender] += amount;
    amountRaised += amount;

    // We assume the token has 18 decimals
    tokenReward.transfer(msg.sender, amount * 10**18 / price);

    FundTransfer(msg.sender, amount, true);
}