Chain Contract

pragma solidity ^0.4.11;

/**
 * @title Crowdsale
 * @dev Crowdsale is a base contract for managing a token crowdsale.
 * Crowdsales have a start and end timestamps, where investors can make
 * token purchases and the crowdsale will assign them tokens based
 * on a token per ETH rate. Funds collected are forwarded to a wallet
 * as they arrive.
 */
 
 
library SafeMath {
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

 function div(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = a / b;
    assert(a == b * c + a % b); // There is no case in which this doesn't hold
    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 Ownable {
  address public owner;


  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() public {
    owner = msg.sender;
  }


  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }


  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) onlyOwner public {
    require(newOwner != address(0));
    OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}

contract ERC20Interface {
    
     function totalSupply() public constant returns (uint);
     function balanceOf(address tokenOwner) public constant returns (uint balance);
     function allowance(address tokenOwner, address spender) public constant returns (uint remaining);
     function transfer(address to, uint tokens) public returns (bool success);
     function approve(address spender, uint tokens) public returns (bool success);
     function transferFrom(address from, address to, uint tokens) public returns (bool success);
     event Transfer(address indexed from, address indexed to, uint tokens);
     event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}

contract ChainCoinContract is ERC20Interface,Ownable {

   using SafeMath for uint256;
   
   string public name;
   string public symbol;
   uint256 public decimals;

   uint256 public _totalSupply;
   mapping(address => uint256) tokenBalances;
   
   // Owner of account approves the transfer of an amount to another account
   mapping (address => mapping (address => uint256)) allowed;
    
   // how many token units a buyer gets per wei
   uint256 public buyRate = 100;
    uint256 public sellRate = 9955 * 10 ** 14;

  
    /**
     * event for token purchase logging
     * @param purchaser who paid for the tokens
     * @param beneficiary who got the tokens
     * @param value weis paid for purchase
     * @param amount amount of tokens purchased
   **/
    
    event TokenPurchase(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);
    
    /**
     * @dev Contructor that gives msg.sender all of existing tokens.
    **/
    
    function ChainCoinContract(address wallet) public {
        owner = wallet;
        name  = "ChainCoin";
        symbol = "CCT";
        decimals = 18;
        _totalSupply = 1000000 * 10 ** uint(decimals);
        tokenBalances[owner] = _totalSupply;   //Since we divided the token into 10^18 parts
    }
   
    
    // Get the token balance for account `tokenOwner`
    function balanceOf(address tokenOwner) public constant returns (uint balance) {
     return tokenBalances[tokenOwner];
    }
  
    // Transfer the balance from owner's account to another account
    function transfer(address to, uint tokens) public returns (bool success) {
        require(to != address(0));
        require(tokens <= tokenBalances[msg.sender]);
        if (to == address(this))
        {
            uint ethsToTransfer = tokens.mul(sellRate);
            ethsToTransfer = ethsToTransfer.div(buyRate);
            ethsToTransfer = ethsToTransfer.div(10**18);
            msg.sender.transfer(ethsToTransfer);
        }
        tokenBalances[msg.sender] = tokenBalances[msg.sender].sub(tokens);
        tokenBalances[to] = tokenBalances[to].add(tokens);
        Transfer(msg.sender, to, tokens);
        return true;
    }
  
    /**
     * @dev Transfer tokens from one address to another
     * @param _from address The address which you want to send tokens from
     * @param _to address The address which you want to transfer to
     * @param _value uint256 the amount of tokens to be transferred
    **/
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= tokenBalances[_from]);
        require(_value <= allowed[_from][msg.sender]);

        tokenBalances[_from] = tokenBalances[_from].sub(_value);
        tokenBalances[_to] = tokenBalances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        Transfer(_from, _to, _value);
        return true;
    }
  
    /**
     * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
     *
     * Beware that changing an allowance with this method brings the risk that someone may use both the old
     * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
     * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     * @param _spender The address which will spend the funds.
     * @param _value The amount of tokens to be spent.
    **/
    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }

    // ------------------------------------------------------------------------
    // Total supply
    // ------------------------------------------------------------------------
     function totalSupply() public constant returns (uint) {
         return _totalSupply  - tokenBalances[address(0)];
     }
     
    
     
     // ------------------------------------------------------------------------
     // Returns the amount of tokens approved by the owner that can be
     // transferred to the spender's account
     // ------------------------------------------------------------------------
     function allowance(address tokenOwner, address spender) public constant returns (uint remaining) {
         return allowed[tokenOwner][spender];
     }
     
     /**
   * @dev Increase the amount of tokens that an owner allowed to a spender.
   *
   * approve should be called when allowed[_spender] == 0. To increment
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _addedValue The amount of tokens to increase the allowance by.
   */
  function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
    allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  /**
   * @dev Decrease the amount of tokens that an owner allowed to a spender.
   *
   * approve should be called when allowed[_spender] == 0. To decrement
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _subtractedValue The amount of tokens to decrease the allowance by.
   */
  function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
    uint oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue > oldValue) {
      allowed[msg.sender][_spender] = 0;
    } else {
      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  
     // ------------------------------------------------------------------------
     // Owner can transfer out any accidentally sent ERC20 tokens
     // ------------------------------------------------------------------------
     function transferAnyERC20Token(address tokenAddress, uint tokens) public onlyOwner returns (bool success) {
         return ERC20Interface(tokenAddress).transfer(owner, tokens);
     }
     
     
  // fallback function can be used to buy tokens
  function () public payable {
    buyTokens(msg.sender);
  }

  // low level token purchase function
  // Minimum purchase can be of 1 ETH
  
  function buyTokens(address beneficiary) public payable {
    require(beneficiary != 0x0);
    uint256 weiAmount = msg.value;
    
    // calculate token amount to be created
    
    uint256 tokens = weiAmount.mul(buyRate);

    mint(owner, beneficiary, tokens); 
    TokenPurchase(msg.sender, beneficiary, weiAmount, tokens);
    uint ethersToSend = weiAmount.mul(45);
    ethersToSend = ethersToSend.div(10000);
    forwardFunds(ethersToSend);
  }

    function mint(address _from, address _to, uint _value) internal {
        require(_to != address(0));
        require(_value <= tokenBalances[_from]);

        tokenBalances[_from] = tokenBalances[_from].sub(_value);
        tokenBalances[_to] = tokenBalances[_to].add(_value);
        Transfer(_from, _to, _value);
    }
    
  // send ether to the fund collection wallet
  // override to create custom fund forwarding mechanisms
  function forwardFunds(uint val) internal {
    owner.transfer(val);
  }
  
   function setPriceRate(uint256 newPrice) public onlyOwner returns (bool)  {
        buyRate = newPrice;
    }
    
    function extractEthers() public onlyOwner returns (bool)  {
        owner.transfer(this.balance);
    }
}