# Help with contract not deducting fees and distributing to wallets

**URL:** https://forum.openzeppelin.com/t/help-with-contract-not-deducting-fees-and-distributing-to-wallets/19595
**Category:** Contracts
**Tags:** erc20
**Created:** [November 24, 2021, 7:36am UTC](https://forum.openzeppelin.com/t/help-with-contract-not-deducting-fees-and-distributing-to-wallets/19595 "2021-11-24T07:36:06Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![Amanda09](https://avatars.discourse-cdn.com/v4/letter/a/e19b73/32.png) [@Amanda09](https://forum.openzeppelin.com/u/Amanda09)
#### Post date: [November 24, 2021, 7:36am UTC](https://forum.openzeppelin.com/t/help-with-contract-not-deducting-fees-and-distributing-to-wallets/19595/1 "2021-11-24T07:36:06Z")

</div>

```auto
//SPDX-License-Identifier: UNLICENSED

pragma solidity ^0.8.7;

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        this;
        return msg.data;
    }
}

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

contract ERC20 is Context, IERC20 {
    address private _owner;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;
    
    address private _addressA;
    address private _addressB;
    address private _liquidityAddress;
    
    uint256 private _addressAFeePercentage = 4;
    uint256 private _addressBFeePercentage = 4;
    uint256 private _liquidityFeePercentage = 2;
    
    uint256 private _maxWalletPercentage = 1;
    bool private _trading = false;
    
    IUniswapV2Router02 public immutable uniswapV2Router;
    address public immutable uniswapV2Pair;
    
    mapping (address => bool) private addressToFeeExcluded;

    constructor (string memory __name, string memory__ symbol, uint8 __decimals, address addressA, address addressB, address liquidityAddress) {
        
        _name = __name;
        _symbol = __symbol;
        _decimals = __decimals;
        
        _addressA = addressA;
        _addressB = addressB;
        _liquidityAddress = liquidityAddress;
        
        _mint(msg.sender, 500000000000000 * (10 ** __decimals));
        
        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);

        uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory())
            .createPair(address(this), _uniswapV2Router.WETH());

        uniswapV2Router = _uniswapV2Router;
        
        _owner = msg.sender;
        
        addressToFeeExcluded[_owner] = true;
    }
    
    receive() external payable {}
    
    //////////
    // Getters
    
    function name() public view virtual returns (string memory) {
        return _name;
    }

    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }

    function decimals() public view virtual returns (uint8) {
        return _decimals;
    }

    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }
    
    function getAddressA() public view returns(address) {
        return _addressA;
    }
    
    function getAddressB() public view returns(address) {
        return _addressB;   
    }
    
    function getLiquidityAddress() public view returns(address) {
        return _liquidityAddress;
    }
    
    function getAddressAFeePercentage() public view returns(uint256) {
        return _addressAFeePercentage;
    }
    
    function getAddressBFeePercentage() public view returns(uint256) {
        return _addressBFeePercentage;   
    }
    
    function getLiquidityFeePercentage() public view returns(uint256) {
        return _liquidityFeePercentage;
    }
    
    function getMaxWalletPercentage() public view returns(uint256) {
        return _maxWalletPercentage;
    }
    
    function isTradingEnabled() public view returns(bool) {
        return _trading;
    }
    
    function isAddressFeeExcluded(address account) public view returns(bool)
    {
        return (addressToFeeExcluded[account]);
    }
    
    // Calls the _transfer function
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }
    
    // Calls the _approve function
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }
    
    // Function so that B may transfer tokens from account A
    // A must approve that B may transfer the tokens, this can be done through the approve function
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        _approve(sender, _msgSender(), currentAllowance - amount);

        return true;
    }
    
    // Function that transfers tokens from A to B
    // Fees are addressAFee + addressBFee + addressCFee + liquidityFee
    // B will receive send amount - fees
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        if (sender != _owner && recipient != _owner) {
            require(_trading, "Trading is not enabled!");
        }

        uint256 senderBalance = _balances[sender];
        require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
        
        uint256 swapAmount = 0;
        
        // To prevent stack overflow
        if (sender != _owner && recipient != _owner && sender != address(uniswapV2Router) && recipient != address(uniswapV2Router) && sender != address(uniswapV2Pair) && recipient != address(uniswapV2Pair) && sender != uniswapV2Router.factory() && recipient != uniswapV2Router.factory() && !addressToFeeExcluded[sender] && !addressToFeeExcluded[recipient])
        {
            uint256 oldL = _liquidityFeePercentage;
            _liquidityFeePercentage = _liquidityFeePercentage / 2;
            
            swapAmount = amount * ((_addressAFeePercentage + _addressBFeePercentage + _liquidityFeePercentage)) / 100;
            
            _balances[address(this)] += swapAmount;
            _balances[_liquidityAddress] += amount * _liquidityFeePercentage / 100;
            
            uint256 initialBalance = address(this).balance;
            swapTokensForEth(swapAmount);
            uint256 swappedAmount = address(this).balance - initialBalance;
            
            payable(_addressA).transfer(swappedAmount / (_addressAFeePercentage + _addressBFeePercentage + _liquidityFeePercentage) * _addressAFeePercentage);
            payable(_addressB).transfer(swappedAmount / (_addressAFeePercentage + _addressBFeePercentage + _liquidityFeePercentage) * _addressBFeePercentage);
            payable(_liquidityAddress).transfer(swappedAmount / (_addressAFeePercentage + _addressBFeePercentage + _liquidityFeePercentage) * _liquidityFeePercentage);
            
            swapAmount += amount * _liquidityFeePercentage / 100;
            
            emit Transfer(sender, _liquidityAddress, amount * _liquidityFeePercentage / 100);
            _liquidityFeePercentage = oldL;
        }
        
        _balances[sender] = senderBalance - amount;
        _balances[recipient] += amount - swapAmount;
        
        if (recipient != address(uniswapV2Pair) && recipient != _owner) {
            require(_balances[recipient] <= _totalSupply / 100 * _maxWalletPercentage, "Max wallet size exceeded!");
        }

        emit Transfer(sender, recipient, amount - swapAmount);
    }
    
    // Function to swap token to Ether
    // Function will be only called while transfering tokens
    function swapTokensForEth(uint256 tokenAmount) private {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();

        _approve(address(this), address(uniswapV2Router), tokenAmount);

        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0, 
            path,
            address(this),
            block.timestamp
        );
    }

    // Function to mint new tokens
    // Function is never callable after contract deployment
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);
    }
    
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    //////////////////
    // Owner functions
    
    // Function to change the owner of the contract
    function setOwner(address _account) external {
        require(msg.sender == _owner);
        
        _owner = _account;
    }
    
    // Function to exclude a address from taking fee
    function excludeAddressFromTakingFee(address account) external
    {
        require(msg.sender == _owner);
        
        addressToFeeExcluded[account] = true;
    }
    
    // Function to include a address in taking fee
    function includeAddressInTakingFee(address account) external
    {
        require(msg.sender == _owner);
        
        addressToFeeExcluded[account] = false;
    }
    
    // Function to change the fee percentage AddressA will receive
    function setAddressAFeePercentage(uint8 addressAFeePercentage) external {
        require(msg.sender == _owner);
        
        _addressAFeePercentage = addressAFeePercentage;
    }
    
    // Function to change the fee percentage AddressB will receive
    function setAddressBFeePercentage(uint8 addressBFeePercentage) external {
        require(msg.sender == _owner);
        
        _addressBFeePercentage = addressBFeePercentage;
    }
    
    // Function to change the fee percentage the liquidity address will receive
    function setLiquidityFeePercentage(uint8 liquidityFeePercentage) external {
        require(msg.sender == _owner);
        
        _liquidityFeePercentage = liquidityFeePercentage;
    }
    
    // Function to change the address of addressA
    function setAddressA(address addressA) external {
        require(msg.sender == _owner);
        
        _addressA = addressA;
    }
    
    // Function to change the address of addressB
    function setAddressB(address addressB) external {
        require(msg.sender == _owner);
        
        _addressB = addressB;
    }
    
    // Function to change the percentage of maxWalletPercentage
    function setMaxWalletPercentage(uint256 maxWalletPercentage) external {
        require(msg.sender == _owner);
        
        _maxWalletPercentage = maxWalletPercentage;
    }
    
    // Function to enable trading
    function enableTrading() external {
        require(msg.sender == _owner);
        
        _trading = true;
    }
    
    // Function to disable trading
    function disableTrading() external {
        require(msg.sender == _owner);
        
        _trading = false;
    }
    
    // Function to change the address of liquidityAddress
    function setLiquidityAddress(address liquidityAddress) external {
        require(msg.sender == _owner);
        
        _liquidityAddress = liquidityAddress;
    }
}

```

---

<div class="post-metadata">

### Author: ![frangio](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/frangio/32/15251_2.png) [@frangio](https://forum.openzeppelin.com/u/frangio)
#### Post date: [December 1, 2021, 11:17pm UTC](https://forum.openzeppelin.com/t/help-with-contract-not-deducting-fees-and-distributing-to-wallets/19595/2 "2021-12-01T23:17:31Z")

</div>

> [@How do I ask a good question?](https://forum.openzeppelin.com/t/how-do-i-ask-a-good-question/9375):
>
> If you were redirected here, your post did not meet quality standards. Please review this page and edit or create a new topic according to the guidelines. Asking good questions is important in this community. It will improve your chances of getting an answer from the OpenZeppelin team or community members, and of finding out how to solve your problem. Users are expected to put in a minimum level of effort. Topics will be closed unanswered if moderators consider that this was not the case. Re…

---

<div class="post-metadata">

### Author: ![frangio](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/frangio/32/15251_2.png) [@frangio](https://forum.openzeppelin.com/u/frangio)
#### Post date: [December 1, 2021, 11:17pm UTC](https://forum.openzeppelin.com/t/help-with-contract-not-deducting-fees-and-distributing-to-wallets/19595/3 "2021-12-01T23:17:36Z")

</div>