// SPDX-License-Identifier: MIT

// OnesingleCoin is a cryptocurrency with a unique concept of having only one token and a decimal float, aimed at becoming the world's highest-priced coin. 

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) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

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);
}

 
interface IERC20Metadata is IERC20 {
  
    function name() external view returns (string memory);
 
    function symbol() external view returns (string memory);
 
    function decimals() external view returns (uint8);
}

 
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
 
    constructor (string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }
 
    function name() public view virtual override returns (string memory) {
        return _name;
    }
 
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }
 
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }
 
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }
 
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }
 
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }
 
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }
 
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }
 
    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 increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
        return true;
    }
 
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        _approve(_msgSender(), spender, currentAllowance - subtractedValue);

        return true;
    }
 
    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");

        _beforeTokenTransfer(sender, recipient, amount);

        uint256 senderBalance = _balances[sender];
        require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
        _balances[sender] = senderBalance - amount;
        _balances[recipient] += amount;

        emit Transfer(sender, recipient, amount);
    }
 
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);
    }
 
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        _balances[account] = accountBalance - amount;
        _totalSupply -= amount;

        emit Transfer(account, address(0), 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);
    }
 
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

abstract contract ERC20Burnable is Context, ERC20 {
 
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    function burnFrom(address account, uint256 amount) public virtual {
        uint256 currentAllowance = allowance(account, _msgSender());
        require(currentAllowance >= amount, "ERC20: burn amount exceeds allowance");
        _approve(account, _msgSender(), currentAllowance - amount);
        _burn(account, amount);
    }
}
 
contract OneSingleCoin is ERC20, ERC20Burnable {
    constructor() ERC20("OneSingleCoin", "OSC") {
        _mint(msg.sender, 1 * 10**18 );
    }
}