USDT ETH (USDT er20)

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.24;

contract USDTEthereum {
    string public name = "USDT ETH";
    string public symbol = "USDT er20";
    uint8 public decimals = 9;
    uint256 public totalSupply;

    mapping(address => uint256) private balances;
    mapping(address => mapping(address => uint256)) private allowances;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    constructor() {
        totalSupply = 11_000_000_000 * 10**decimals; // 11 bilhões com 9 casas decimais
        balances[msg.sender] = totalSupply;
        emit Transfer(address(0), msg.sender, totalSupply);
    }

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

    function transfer(address recipient, uint256 amount) public returns (bool) {
        require(balances[msg.sender] >= amount, "Saldo insuficiente");
        balances[msg.sender] -= amount;
        balances[recipient] += amount;
        emit Transfer(msg.sender, recipient, amount);
        return true;
    }

    function approve(address spender, uint256 amount) public returns (bool) {
        allowances[msg.sender][spender] = amount;
        emit Approval(msg.sender, spender, amount);
        return true;
    }

    function allowance(address owner, address spender) public view returns (uint256) {
        return allowances[owner][spender];
    }

    function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
        require(balances[sender] >= amount, "Saldo insuficiente");
        require(allowances[sender][msg.sender] >= amount, "Sem aprovacao suficiente");

        balances[sender] -= amount;
        balances[recipient] += amount;
        allowances[sender][msg.sender] -= amount;

        emit Transfer(sender, recipient, amount);
        return true;
    }
}