Contract Source Code:
File 1 of 1 : ERC20
// SPDX-License-Identifier: MIT
// ----------------------------------------------------------------------------
// Token Standard
// By cyphersapiens
// Hello world
// ----------------------------------------------------------------------------
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);
}
interface IERC20Metadata is IERC20 {
function name() external view returns (string memory);
function symbol() external view returns (string memory);
function decimals() external view returns (uint8);
}
interface IERC165 {
function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
abstract contract ERC165 is IERC165 {
function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
return interfaceId == type(IERC165).interfaceId;
}
}
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;
}
}
}
library UnsafeMath {
function unsafe_add(uint256 a, uint256 b) internal pure returns (uint256) {
unchecked {
return a + b;
}
}
function unsafe_sub(uint256 a, uint256 b) internal pure returns (uint256) {
unchecked {
return a - b;
}
}
function unsafe_div(uint256 a, uint256 b) internal pure returns (uint256) {
unchecked {
uint256 result;
assembly {
result := div(a, b)
}
return result;
}
}
function unsafe_mul(uint256 a, uint256 b) internal pure returns (uint256) {
unchecked {
return a * b;
}
}
function unsafe_increment(uint256 a) internal pure returns (uint256) {
unchecked {
return ++a;
}
}
function unsafe_decrement(uint256 a) internal pure returns (uint256) {
unchecked {
return --a;
}
}
}
library Address {
function isContract(address account) internal view returns (bool) {
bytes32 codehash;
bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
assembly { codehash := extcodehash(account) }
return (codehash != accountHash && codehash != 0x0);
}
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return _functionCallWithValue(target, data, 0, errorMessage);
}
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
return _functionCallWithValue(target, data, value, errorMessage);
}
function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
require(isContract(target), "Address: call to non-contract");
(bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
if (success) {
return returndata;
} else {
if (returndata.length > 0) {
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
library SafeERC20 {
using Address for address;
function safeTransfer(IERC20 token, address to, uint value) internal {
callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(IERC20 token, address from, address to, uint value) internal {
callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
function safeApprove(IERC20 token, address spender, uint value) internal {
require((value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function callOptionalReturn(IERC20 token, bytes memory data) private {
require(address(token).isContract(), "SafeERC20: call to non-contract");
(bool success, bytes memory returndata) = address(token).call(data);
require(success, "SafeERC20: low-level call failed");
if (returndata.length > 0) {
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
contract Ownable is Context {
address private _owner;
address private _previousOwner;
uint256 private _lockTime;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
constructor () {
address msgSender = _msgSender();
_owner = msg.sender;
emit OwnershipTransferred(address(0), msgSender);
}
function owner() public view returns (address) {
return _owner;
}
modifier onlyOwner() {
require(_owner == _msgSender(), "Ownable: caller is not the owner");
_;
}
function renounceOwnership() public virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
abstract contract Pausable is Context {
event Paused(address account);
event Unpaused(address account);
bool private _paused;
constructor() {
_paused = false;
}
modifier whenNotPaused() {
_requireNotPaused();
_;
}
modifier whenPaused() {
_requirePaused();
_;
}
function paused() public view virtual returns (bool) {
return _paused;
}
function _requireNotPaused() internal view virtual {
require(!paused(), "Pausable: paused");
}
function _requirePaused() internal view virtual {
require(paused(), "Pausable: not paused");
}
function _pause() internal virtual whenNotPaused {
_paused = true;
emit Paused(_msgSender());
}
function _unpause() internal virtual whenPaused {
_paused = false;
emit Unpaused(_msgSender());
}
}
contract ERC20 is IERC20, IERC20Metadata, ERC165, Context, Ownable {
using SafeMath for uint256;
using UnsafeMath for uint256;
using Address for address;
using SafeERC20 for IERC20;
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
string private _name = "Krohtcoin";
string private _symbol = "KRTC";
uint8 private _decimals = 9;
uint256 private _totalSupply = 1618033988000000000;
uint256 private _s_foobar;
constructor() {
_balances[msg.sender] = _totalSupply;
}
function safeDecrement(uint256 count) public {
for (uint256 i = count; i > 0; --i) {
_s_foobar = i;
}
}
function safeIncrement(uint256 count) public {
for (uint256 i = 0; i < count; ++i) {
_s_foobar = i;
}
}
function unsafeDecrement(uint256 count) public {
for (uint256 i = count; i > 0; i = i.unsafe_decrement()) {
_s_foobar = i;
}
}
function unsafeIncrement(uint256 count) public {
for (uint256 i = 0; i < count; i = i.unsafe_increment()) {
_s_foobar = i;
}
}
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 _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 transfer(address to, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_transfer(owner, to, 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) {
address owner = _msgSender();
_approve(owner, spender, amount);
return true;
}
function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, amount);
return true;
}
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
address owner = _msgSender();
_approve(owner, spender, allowance(owner, spender) + addedValue);
return true;
}
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
address owner = _msgSender();
uint256 currentAllowance = allowance(owner, spender);
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
return true;
}
function _transfer(address from, address to, uint256 amount) internal virtual {
require(from != address(0), "ERC20: transfer from the zero address");
require(to != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(from, to, amount);
uint256 fromBalance = _balances[from];
require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[from] = fromBalance - amount;
_balances[to] += amount;
}
emit Transfer(from, to, amount);
_afterTokenTransfer(from, to, 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 _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
uint256 currentAllowance = allowance(owner, spender);
if (currentAllowance != type(uint256).max) {
require(currentAllowance >= amount, "ERC20: insufficient allowance");
unchecked {
_approve(owner, spender, currentAllowance - amount);
}
}
}
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}
function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
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;
unchecked {
_balances[account] += amount;
}
emit Transfer(address(0), account, amount);
_afterTokenTransfer(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");
unchecked {
_balances[account] = accountBalance - amount;
_totalSupply -= amount;
}
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
}
abstract contract ERC20Burnable is Context, ERC20 {
function burn(uint256 amount) internal virtual {
_burn(_msgSender(), amount);
}
function burnFrom(address account, uint256 amount) internal virtual {
_spendAllowance(account, _msgSender(), amount);
_burn(account, amount);
}
}
abstract contract ERC20Capped is ERC20 {
uint256 private immutable _cap;
constructor(uint256 cap_) {
require(cap_ > 0, "ERC20Capped: cap is 0");
_cap = cap_;
}
function cap() public view virtual returns (uint256) {
return _cap;
}
function _mint(address account, uint256 amount) internal virtual override {
require(ERC20.totalSupply() + amount <= cap(), "ERC20Capped: cap exceeded");
super._mint(account, amount);
}
}
abstract contract ERC20Pausable is ERC20, Pausable {
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual override {
super._beforeTokenTransfer(from, to, amount);
require(!paused(), "ERC20Pausable: token transfer while paused");
}
}