pragma solidity ^0.8.0;



interface IERC20 {

    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function allowance(address owner, address spender) external view returns (uint256);

    function transfer(address recipient, uint256 amount) external returns (bool);
    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);
}
contract IAV is IERC20 {

    string public constant name = "In Argentum Veritas";
    string public constant symbol = "IAV";
    uint8 public constant decimals = 15;


    mapping(address => uint256) balances;

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

    uint256 totalSupply_ = 2000 ether;


   constructor() {
               totalSupply_ = 2000 ether;
    balances[msg.sender] = totalSupply_;
    }

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

    function balanceOf(address tokenOwner) public override view returns (uint256) {
        return balances[tokenOwner];
    }

    function transfer(address receiver, uint256 numTokens) public override returns (bool) {
        require(numTokens <= balances[msg.sender]);
        balances[msg.sender] = balances[msg.sender]-numTokens;
        balances[receiver] = balances[receiver]+numTokens;
        emit Transfer(msg.sender, receiver, numTokens);
        return true;
    }

    function approve(address delegate, uint256 numTokens) public override returns (bool) {
        allowed[msg.sender][delegate] = numTokens;
        emit Approval(msg.sender, delegate, numTokens);
        return true;
    }

    function allowance(address owner, address delegate) public override view returns (uint) {
        return allowed[owner][delegate];
    }

    function transferFrom(address owner, address buyer, uint256 numTokens) public override returns (bool) {
        require(numTokens <= balances[owner]);
        require(numTokens <= allowed[owner][msg.sender]);

        balances[owner] = balances[owner]-numTokens;
        allowed[owner][msg.sender] = allowed[owner][msg.sender]-numTokens;
        balances[buyer] = balances[buyer]+numTokens;
        emit Transfer(owner, buyer, numTokens);
        return true;
    }

}


contract Swap {

    event Bought(uint256 amount);
    event Sold(uint256 amount);
    IERC20 _token;
    address owner;
   
 


    constructor(address token) {
        _token = IERC20(token);
        owner = msg.sender;
    }
     modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    function buy() payable public {
        uint256 amountTobuy = msg.value;
        uint256 dexBalance = _token.balanceOf(address(this));
        require(amountTobuy > 0, "You need to send some ether");
        require(amountTobuy <= dexBalance, "Not enough tokens in the reserve");
        _token.transfer(msg.sender, amountTobuy);
        emit Bought(amountTobuy);
    }

    function sell(uint256 amount) public {
        require(amount > 0, "You need to sell at least some tokens");
        uint256 allowance = _token.allowance(msg.sender, address(this));
        require(allowance >= amount, "Check the token allowance");
        _token.transferFrom(msg.sender, address(this), amount);
        payable(msg.sender).transfer(amount);
        emit Sold(amount);
    }



    function withdrawToken(address _tokenContract, uint256 _amount) external onlyOwner {
        IERC20 tokenContract = IERC20(_tokenContract);
        
        // transfer the token from address of this contract
        // to address of the user (executing the withdrawToken() function)
        tokenContract.transfer(msg.sender, _amount);
    }

    function _SendEth(uint256 amount) public payable onlyOwner {
     payable(msg.sender).transfer(amount);
}







     receive() external payable {
        uint256 amountTobuy = msg.value;
         _token.transfer(msg.sender, amountTobuy);
        emit Bought(msg.value);
    }

    fallback() external payable {
        
           uint256 amountTobuy = msg.value;
         _token.transfer(msg.sender, amountTobuy);
        emit Bought(msg.value);
    }

    

}



 

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