ETH标准合约

墨蓝 2022-10-10 11:29 144阅读 0赞

pragma solidity ^0.4.16;

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 \{  
    // Public variables of the token  
    string public name;  
    string public symbol;  
    uint8 public decimals = 18;  
    // 18 decimals is the strongly suggested default, avoid changing it  
    uint256 public totalSupply;

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

// This generates a public event on the blockchain that will notify clients  
    event Transfer(address indexed from, address indexed to, uint256 value);  
      
    // This generates a public event on the blockchain that will notify clients  
    event Approval(address indexed \_owner, address indexed \_spender, uint256 \_value);

// This notifies clients about the amount burnt  
    event Burn(address indexed from, uint256 value);

/\*\*  
     \* Constrctor function  
     \*  
     \* Initializes contract with initial supply tokens to the creator of the contract  
     \*/  
    function TokenERC20(  
        uint256 initialSupply,  
        string tokenName,  
        string tokenSymbol  
    ) public \{  
        totalSupply = initialSupply \* 10 \*\* uint256(decimals);  // Update total supply with the decimal amount  
        balanceOf\[msg.sender\] = totalSupply;                // Give the creator all initial tokens  
        name = tokenName;                                   // Set the name for display purposes  
        symbol = tokenSymbol;                               // Set the symbol for display purposes  
    \}

/\*\*  
     \* Internal transfer, only can be called by this contract  
     \*/  
    function \_transfer(address \_from, address \_to, uint \_value) internal \{  
        // Prevent transfer to 0x0 address. Use burn() instead  
        require(\_to != 0x0);  
        // Check if the sender has enough  
        require(balanceOf\[\_from\] >= \_value);  
        // Check for overflows  
        require(balanceOf\[\_to\] + \_value > balanceOf\[\_to\]);  
        // Save this for an assertion in the future  
        uint previousBalances = balanceOf\[\_from\] + balanceOf\[\_to\];  
        // Subtract from the sender  
        balanceOf\[\_from\] -= \_value;  
        // Add the same to the recipient  
        balanceOf\[\_to\] += \_value;  
        emit Transfer(\_from, \_to, \_value);  
        // Asserts are used to use static analysis to find bugs in your code. They should never fail  
        assert(balanceOf\[\_from\] + balanceOf\[\_to\] == previousBalances);  
    \}

/\*\*  
     \* Transfer tokens  
     \*  
     \* Send \`\_value\` tokens to \`\_to\` from your account  
     \*  
     \* @param \_to The address of the recipient  
     \* @param \_value the amount to send  
     \*/  
    function transfer(address \_to, uint256 \_value) public returns (bool success) \{  
        \_transfer(msg.sender, \_to, \_value);  
        return true;  
    \}

/\*\*  
     \* Transfer tokens from other address  
     \*  
     \* Send \`\_value\` tokens to \`\_to\` in behalf of \`\_from\`  
     \*  
     \* @param \_from The address of the sender  
     \* @param \_to The address of the recipient  
     \* @param \_value the amount to send  
     \*/  
    function transferFrom(address \_from, address \_to, uint256 \_value) public returns (bool success) \{  
        require(\_value <= allowance\[\_from\]\[msg.sender\]);     // Check allowance  
        allowance\[\_from\]\[msg.sender\] -= \_value;  
        \_transfer(\_from, \_to, \_value);  
        return true;  
    \}

/\*\*  
     \* Set allowance for other address  
     \*  
     \* Allows \`\_spender\` to spend no more than \`\_value\` tokens in your behalf  
     \*  
     \* @param \_spender The address authorized to spend  
     \* @param \_value the max amount they can spend  
     \*/  
    function approve(address \_spender, uint256 \_value) public  
        returns (bool success) \{  
        allowance\[msg.sender\]\[\_spender\] = \_value;  
        emit Approval(msg.sender, \_spender, \_value);  
        return true;  
    \}

/\*\*  
     \* Set allowance for other address and notify  
     \*  
     \* Allows \`\_spender\` to spend no more than \`\_value\` tokens in your behalf, and then ping the contract about it  
     \*  
     \* @param \_spender The address authorized to spend  
     \* @param \_value the max amount they can spend  
     \* @param \_extraData some extra information to send to the approved contract  
     \*/  
    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;  
        \}  
    \}

/\*\*  
     \* Destroy tokens  
     \*  
     \* Remove \`\_value\` tokens from the system irreversibly  
     \*  
     \* @param \_value the amount of money to burn  
     \*/  
    function burn(uint256 \_value) public returns (bool success) \{  
        require(balanceOf\[msg.sender\] >= \_value);   // Check if the sender has enough  
        balanceOf\[msg.sender\] -= \_value;            // Subtract from the sender  
        totalSupply -= \_value;                      // Updates totalSupply  
        emit Burn(msg.sender, \_value);  
        return true;  
    \}

/\*\*  
     \* Destroy tokens from other account  
     \*  
     \* Remove \`\_value\` tokens from the system irreversibly on behalf of \`\_from\`.  
     \*  
     \* @param \_from the address of the sender  
     \* @param \_value the amount of money to burn  
     \*/  
    function burnFrom(address \_from, uint256 \_value) public returns (bool success) \{  
        require(balanceOf\[\_from\] >= \_value);                // Check if the targeted balance is enough  
        require(\_value <= allowance\[\_from\]\[msg.sender\]);    // Check allowance  
        balanceOf\[\_from\] -= \_value;                         // Subtract from the targeted balance  
        allowance\[\_from\]\[msg.sender\] -= \_value;             // Subtract from the sender's allowance  
        totalSupply -= \_value;                              // Update totalSupply  
        emit Burn(\_from, \_value);  
        return true;  
    \}  
\}

/\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*/  
/\*       ADVANCED TOKEN STARTS HERE       \*/  
/\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*/

contract Cartycoin is owned, TokenERC20 \{

uint256 public sellPrice;  
    uint256 public buyPrice;

mapping (address => bool) public frozenAccount;

/\* This generates a public event on the blockchain that will notify clients \*/  
    event FrozenFunds(address target, bool frozen);

/\* Initializes contract with initial supply tokens to the creator of the contract \*/  
    function Cartycoin(  
        uint256 initialSupply,  
        string tokenName,  
        string tokenSymbol  
    ) TokenERC20(initialSupply, tokenName, tokenSymbol) public \{\}

/\* Internal transfer, only can be called by this contract \*/  
    function \_transfer(address \_from, address \_to, uint \_value) internal \{  
        require (\_to != 0x0);                               // Prevent transfer to 0x0 address. Use burn() instead  
        require (balanceOf\[\_from\] >= \_value);               // Check if the sender has enough  
        require (balanceOf\[\_to\] + \_value >= balanceOf\[\_to\]); // Check for overflows  
        require(!frozenAccount\[\_from\]);                     // Check if sender is frozen  
        require(!frozenAccount\[\_to\]);                       // Check if recipient is frozen  
        balanceOf\[\_from\] -= \_value;                         // Subtract from the sender  
        balanceOf\[\_to\] += \_value;                           // Add the same to the recipient  
        emit Transfer(\_from, \_to, \_value);  
    \}

/// @notice Create \`mintedAmount\` tokens and send it to \`target\`  
    /// @param target Address to receive the tokens  
    /// @param mintedAmount the amount of tokens it will receive  
    function mintToken(address target, uint256 mintedAmount) onlyOwner public \{  
        balanceOf\[target\] += mintedAmount;  
        totalSupply += mintedAmount;  
        emit Transfer(0, this, mintedAmount);  
        emit Transfer(this, target, mintedAmount);  
    \}

/// @notice \`freeze? Prevent | Allow\` \`target\` from sending & receiving tokens  
    /// @param target Address to be frozen  
    /// @param freeze either to freeze it or not  
    function freezeAccount(address target, bool freeze) onlyOwner public \{  
        frozenAccount\[target\] = freeze;  
        emit FrozenFunds(target, freeze);  
    \}

/// @notice Allow users to buy tokens for \`newBuyPrice\` eth and sell tokens for \`newSellPrice\` eth  
    /// @param newSellPrice Price the users can sell to the contract  
    /// @param newBuyPrice Price users can buy from the contract  
    function setPrices(uint256 newSellPrice, uint256 newBuyPrice) onlyOwner public \{  
        sellPrice = newSellPrice;  
        buyPrice = newBuyPrice;  
    \}

/// @notice Buy tokens from contract by sending ether  
    function buy() payable public \{  
        uint amount = msg.value / buyPrice;               // calculates the amount  
        \_transfer(this, msg.sender, amount);              // makes the transfers  
    \}

/// @notice Sell \`amount\` tokens to contract  
    /// @param amount amount of tokens to be sold  
    function sell(uint256 amount) public \{  
        address myAddress = this;  
        require(myAddress.balance >= amount \* sellPrice);      // checks if the contract has enough ether to buy  
        \_transfer(msg.sender, this, amount);              // makes the transfers  
        msg.sender.transfer(amount \* sellPrice);          // sends ether to the seller. It's important to do this last to avoid recursion attacks  
    \}  
\}