erc20 智能合约中的交易费用

Question

I ran into an issue...

I built a erc20 smart contract but dont know how to add features such as a transaction fees on each transaction.

How to code a transaction fees on each transaction?

Answer 1

Not sure exactly what you're asking - but if you want to take a cut of the transaction whenever an ERC20 is transferred you could do this:.

In the ERC20 contract: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol

Add owner to state, and update the constructor to be:

    address contractDeployer;
    uint txCharge = 1 // As we can't store decimals (1 = 1%)

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
        contractDeployer= msg.sender;
    }

Then, modify the transfer function to be:

function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        // Transfers 1% of the amount to send to the contract deployer (you)
        _transfer(owner, contractDeployer, amount * txCharge / 100); 
        // Transfers the remaining 99% to the actual recipient
        _transfer(owner, to, amount - (amount * txCharge/100);
        return true;
    }