將 ERC20 代幣從一個智能合約發送到另一個智能合約的問題

Question

我有一個 ERC20 代幣（加密貨幣）並想向 VulnerableTokenSale 智能合約發送一些代幣，但它顯示代幣余額為零（get_balanceToken 函數）。 有可能這樣做嗎？ 我在以太坊網站上使用 Remix。

     contract VulnerableTokenSale {
        address public wallet;
        uint256 rate;
        ERC20 public token;
        address public owner;


        mapping(address => uint256) public balances;
        address [] beneficiaries;

        modifier onlyOwner() {
            require(msg.sender == owner, "not owner");
            _;
        }

        constructor(address _wallet, uint256 _rate, ERC20 _token) 
            public {
                wallet = _wallet;
                rate = _rate;
                token = _token;
                owner = msg.sender;
            }

        function sendTokensWithRatio(uint256 _numerator, uint256 _denominator) external onlyOwner {

            require(_numerator <= _denominator);

            for(uint256 i = 0; i < beneficiaries.length; i++){
                address beneficiary = beneficiaries[i];
                uint256 balance = balances[beneficiary];

                if(balance > 0) {
                    uint256 amount = balance * _numerator;
                    amount = amount / _denominator;
                    balances[beneficiary] = balance - amount;
                    token.transfer(beneficiary, amount);
                }
            }
        }

        function purchaseTokens() public payable{
            uint256 weiAmount = msg.value;

            uint256 _tokenAmount = weiAmount * rate;
            beneficiaries.push(msg.sender);
            balances[msg.sender] = balances[msg.sender] + _tokenAmount;
        }

    }

Answer 1

認為您的構造函數略有錯誤，我從未見過有人直接接受 ERC 令牌。

我的合同中有這樣的內容：

constructor(address _wallet, uint256 _rate, address _tokenAddress) public {
    wallet = _wallet;
    rate = _rate;
    token = ERC20(_tokenAddress);
    owner = msg.sender;
}

請注意，您需要 ERC20 接口才能進行上述操作：

interface ERC20 {
    function totalSupply() public view returns (uint);
    function balanceOf(address tokenOwner) public view returns (uint balance);
    function allowance(address tokenOwner, address spender) public view returns (uint remaining);
    function transfer(address to, uint tokens) public returns (bool success);
    function approve(address spender, uint tokens) public returns (bool success);
    function transferFrom(address from, address to, uint tokens) public returns (bool success);
    // optional
    function name() external view returns (string);
    function symbol() external view returns (string);
    function decimals() external view returns (string);

    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}