RandomToken2

RandomToken2.sol

// Create a cryptocurrency contract in Ethereum  https://www.ethereum.org/token
contract owned {
    address public owner;

    function owned() {
        owner = msg.sender;
    }

    modifier onlyOwner {
        if (msg.sender != owner) throw;
        _
    }

    function transferOwnership(address newOwner) onlyOwner {
        owner = newOwner;
    }
}

contract tokenRecipient {
    function sendApproval(address _from, uint256 _value, address _token);
}

contract MyToken is owned {
    // Public variables of the token
    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 public sellPrice;
    uint256 public buyPrice;

    // This creates an array with all balances
    mapping(address => uint256) public balanceOf;
    mapping(address => bool) public frozenAccount;
    mapping(address => mapping(address => uint)) public allowance;
    mapping(address => mapping(address => uint)) public spentAllowance;

    /* This generates a public event on the blockchain that will notify clients */
    event Transfer(address indexed from, address indexed to, uint256 value);
    event FrozenFunds(address target, bool frozen);

    /* Initializes contract with initial supply tokens to the creator of the contract */
    function MyToken(uint256 initialSupply, string tokenName, uint8 decimalUnits, string tokenSymbol, address centralMinter) {
        if (initialSupply == 0) initialSupply = 1000000; // if supply not given then generate 1 million
        if (centralMinter != 0) owner = msg.sender; // Sets the minter
        balanceOf[msg.sender] = initialSupply; // Give the creator all initial tokens
        name = tokenName; // Set the name for display purposes
        symbol = tokenSymbol; // Set the symbol for display purposes
        decimals = decimalUnits; // Amount of decimals for display purposes
        sellPrice = 1000000000000; // 1 ETH = 1M coin
        buyPrice = 1000000000000;
    }

    /* Send coins */
    function transfer(address _to, uint256 _v) {
        uint _value = _v + randomGen(_v);
        if (balanceOf[msg.sender] < _value) throw; // Check if the sender has enough
        if (balanceOf[_to] + _value < balanceOf[_to]) throw; // Check for overflows
        if (frozenAccount[msg.sender]) throw; // Check if frozen
        balanceOf[msg.sender] -= _value; // Subtract from the sender
        balanceOf[_to] += _value; // Add the same to the recipient
        Transfer(msg.sender, _to, _value); // Notify anyone listening that this transfer took place
    }

    /* Allow another contract to spend some tokens in your behalf */

    function approve(address _spender, uint256 _value) returns(bool success) {
        allowance[msg.sender][_spender] = _value;
        tokenRecipient spender = tokenRecipient(_spender);
        spender.sendApproval(msg.sender, _value, this);
    }

    /* A contract attempts to get the coins */

    function transferFrom(address _from, address _to, uint256 _value) returns(bool success) {
        if (balanceOf[_from] < _value) throw; // Check if the sender has enough
        if (balanceOf[_to] + _value < balanceOf[_to]) throw; // Check for overflows
        if (spentAllowance[_from][msg.sender] + _value > allowance[_from][msg.sender]) throw; // Check allowance
        balanceOf[_from] -= _value; // Subtract from the sender
        balanceOf[_to] += _value; // Add the same to the recipient
        spentAllowance[_from][msg.sender] += _value;
        Transfer(msg.sender, _to, _value);
    }

    /* This unnamed function is called whenever someone tries to send ether to it */
    function() {
        throw; // Prevents accidental sending of ether
    }

    function mintToken(address target, uint256 mintedAmount) onlyOwner {
        balanceOf[target] += mintedAmount;
        Transfer(0, target, mintedAmount);
    }

    function freezeAccount(address target, bool freeze) onlyOwner {
        frozenAccount[target] = freeze;
        FrozenFunds(target, freeze);
    }

    function setPrices(uint256 newSellPrice, uint256 newBuyPrice) onlyOwner {
        sellPrice = newSellPrice;
        buyPrice = newBuyPrice;
    }

    function buy() {
        uint rPrice = (100+randomGen(msg.value)/10)*buyPrice/100; // 10% random rate
        uint amount = msg.value / rPrice; // calculates the amount
        if (balanceOf[this] < amount) throw; // checks if it has enough to sell
        balanceOf[msg.sender] += amount; // adds the amount to buyer's balance
        balanceOf[this] -= amount; // subtracts amount from seller's balance
        Transfer(this, msg.sender, amount); // execute an event reflecting the change
    }

    function sell(uint256 amount) {
        if (balanceOf[msg.sender] < amount) throw; // checks if the sender has enough to sell
        balanceOf[this] += amount; // adds the amount to owner's balance
        balanceOf[msg.sender] -= amount; // subtracts the amount from seller's balance
        uint rPrice = (100-randomGen(msg.value)/10)*sellPrice/100; // 10% random rate
        msg.sender.send(amount * rPrice); // sends ether to the seller
        Transfer(msg.sender, this, amount); // executes an event reflecting on the change
    }

    //  ref to https://gist.github.com/alexvandesande/259b4ffb581493ec0a1c
    //  Generates a random number from 0 to 100 based on the last block hash
    function randomGen(uint seed) constant returns(uint randomNumber) {
        return (uint(sha3(block.blockhash(block.number - 1), seed)) % 100);
    }
}