// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;


abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

   
    constructor() {
        _transferOwnership(_msgSender());
    }

    
    function owner() public view virtual returns (address) {
        return _owner;
    }

   
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

  
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

   
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


library SafeMath {
    
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

   
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
           
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

   
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

   
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

   
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

 
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

   
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

  
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}


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);
}

contract Qmall is  Ownable , IERC20 {
 using SafeMath for uint256;
    
    mapping (address => uint256) private _balances;
    
    mapping (address => mapping (address => uint256)) private _allowances;
    
    uint256 private _totalSupply;
    uint8 private _decimals;
    string private _symbol;
    string private _name;
    
    constructor() {
        _name = "Qmall Token";
        _symbol = "QMALL";
        _decimals = 18;
        _totalSupply = 100000000 * 10 ** 18;
        _balances[_msgSender()] = _totalSupply;
        
        emit Transfer(address(0), _msgSender(), _totalSupply);
    }

   
    function getOwner() external view  returns (address) {
        return owner();
    }
    
    
    function decimals() external view  returns (uint8) {
        return _decimals;
    }
    
   
    function symbol() external view  returns (string memory) {
        return _symbol;
    }
   
    function name() external view  returns (string memory) {
        return _name;
    }
    
    
    function totalSupply() external view override returns (uint256) {
        return _totalSupply;
    }
    
   
    function balanceOf(address account) external view override returns (uint256) {
        return _balances[account];
    }
    
    
    function burn(uint256 amount) 
        public       
        
    {
        _burn(msg.sender, amount);
    }

    function _mint(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: mint to the zero address");

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    function _burn(address from, uint value) internal {
        _balances[from] = _balances[from].sub(value);
        _totalSupply = _totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }
    
    
   
    function transfer(address recipient, uint256 amount) public override  returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }
    
    
    
    
    function allowance(address owner, address spender) external view override returns (uint256) {
        return _allowances[owner][spender];
    }
    
 
    function approve(address spender, uint256 amount) public  override  returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }
    
   
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public override  returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(
            sender,
            _msgSender(),
            _allowances[sender][_msgSender()].sub(
                amount,
                "ERC20: transfer amount exceeds allowance"
            )
        );
        return true;
    }
    
   
    function increaseAllowance(address spender, uint256 addedValue)
        public
        
        returns (bool)
    {
        _approve(
            _msgSender(),
            spender,
            _allowances[_msgSender()][spender].add(addedValue)
        );
        return true;
    }
    
    
    function decreaseAllowance(address spender, uint256 subtractedValue)
        public
        
        returns (bool)
    {
        _approve(
            _msgSender(),
            spender,
            _allowances[_msgSender()][spender].sub(
                subtractedValue,
                "ERC20: decreased allowance below zero"
            )
        );
        return true;
    }
    
    
    function _transfer(address sender, address recipient, uint256 amount) internal {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");
        
        
        
        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }
    function withdrawToken(address _tokenContract, uint256 _amount) external onlyOwner {
        IERC20 token = IERC20(_tokenContract);
        
       
        token.transfer(msg.sender, _amount);
    }
    
    
    function _approve(address owner, address spender, uint256 amount) internal {
        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);
    }
}