pragma solidity ^0.4.16; library SafeMath { function mul(uint256 a, uint256 b) internal pure returns (uint256) { if (a == 0) { return 0; } uint256 c = a * b; assert(c / a == b); return c; } function div(uint256 a, uint256 b) internal pure returns (uint256) { uint256 c = a / b; return c;} function sub(uint256 a, uint256 b) internal pure returns (uint256) { assert(b <= a); return a - b; } function add(uint256 a, uint256 b) internal pure returns (uint256) { uint256 c = a + b; assert(c >= a); return c; } } contract owned { address public owner; function owned() public { owner = msg.sender; } modifier onlyOwner { require(msg.sender == owner); _; } function transferOwnership(address newOwner) onlyOwner public { owner = newOwner; } } interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external; } contract TokenERC20 { using SafeMath for uint256; string public name; string public symbol; uint8 public decimals = 18; uint256 public totalSupply; mapping (address => uint256) public balanceOf; mapping (address => mapping (address => uint256)) public allowance; event Transfer(address indexed from, address indexed to, uint256 value); event Burn(address indexed from, uint256 value); function TokenERC20( uint256 initialSupply, string tokenName, string tokenSymbol ) public { totalSupply = initialSupply * 10 ** uint256(decimals); balanceOf[msg.sender] = totalSupply; name = tokenName; symbol = tokenSymbol; } function _transfer(address _from, address _to, uint _value) internal { require(_to != 0x0); require(balanceOf[_from] >= _value); require(balanceOf[_to].add(_value) > balanceOf[_to]); uint previousBalances = balanceOf[_from].add(balanceOf[_to]); balanceOf[_from] = balanceOf[_from].sub(_value); balanceOf[_to] = balanceOf[_to].add(_value); emit Transfer(_from, _to, _value); assert(balanceOf[_from] + balanceOf[_to] == previousBalances); } function transfer(address _to, uint256 _value) public { _transfer(msg.sender, _to, _value); } function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) { require(_value <= allowance[_from][msg.sender]); allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value); _transfer(_from, _to, _value); return true; } function approve(address _spender, uint256 _value) public returns (bool success) { allowance[msg.sender][_spender] = _value; return true; } function approveAndCall(address _spender, uint256 _value, bytes _extraData) public returns (bool success) { tokenRecipient spender = tokenRecipient(_spender); if (approve(_spender, _value)) { spender.receiveApproval(msg.sender, _value, this, _extraData); return true; } } function burn(uint256 _value) public returns (bool success) { require(balanceOf[msg.sender] >= _value); balanceOf[msg.sender] = balanceOf[msg.sender].sub(_value); totalSupply = totalSupply.sub(_value); emit Burn(msg.sender, _value); return true; } function burnFrom(address _from, uint256 _value) public returns (bool success) { require(balanceOf[_from] >= _value); require(_value <= allowance[_from][msg.sender]); balanceOf[_from] = balanceOf[_from].sub(_value); allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value); totalSupply = totalSupply.sub(_value); emit Burn(_from, _value); return true; } } contract MyAdvancedToken is owned, TokenERC20 { using SafeMath for uint256; uint256 public sellPrice; uint256 public buyPrice; mapping (address => bool) public frozenAccount; event FrozenFunds(address target, bool frozen); function MyAdvancedToken( uint256 initialSupply, string tokenName, string tokenSymbol ) TokenERC20(initialSupply, tokenName, tokenSymbol) public {} function _transfer(address _from, address _to, uint _value) internal { require (_to != 0x0); require (balanceOf[_from] >= _value); require (balanceOf[_to].add(_value) >= balanceOf[_to]); require(!frozenAccount[_from]); require(!frozenAccount[_to]); balanceOf[_from] = balanceOf[_from].sub(_value); balanceOf[_to] = balanceOf[_to].add(_value); emit Transfer(_from, _to, _value); } function mintToken(address target, uint256 mintedAmount) onlyOwner public { balanceOf[target] = balanceOf[target].add(mintedAmount); totalSupply = totalSupply.add(mintedAmount); emit Transfer(0, this, mintedAmount); emit Transfer(this, target, mintedAmount); } function freezeAccount(address target, bool freeze) onlyOwner public { frozenAccount[target] = freeze; emit FrozenFunds(target, freeze); } function setPrices(uint256 newSellPrice, uint256 newBuyPrice) onlyOwner public { sellPrice = newSellPrice; buyPrice = newBuyPrice; } function buy() payable public { uint amount = msg.value.div(buyPrice); _transfer(this, msg.sender, amount); } function sell(uint256 amount) public { require(address(this).balance >= amount.mul(sellPrice)); _transfer(msg.sender, this, amount); msg.sender.transfer(amount.mul(sellPrice));}}