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    My personal opinion about this Blockchain of ETH

    Jun Huang Wũ
    Jun Huang Wũ
    Admin


    Tổng số bài gửi : 10
    Join date : 10/02/2019
    Age : 40
    Đến từ : Hanoi, Vietnam

    My personal opinion about this Blockchain of ETH Empty My personal opinion about this Blockchain of ETH

    Bài gửi by Jun Huang Wũ Tue Feb 12, 2019 10:06 am

    The open Blockchain source code which I give above coule be used Object-Oriented Program Languages (OOPL) (Java mainly) to write.

    Does anyone (who) has another idea..??!.. Question
    Jun Huang Wũ
    Jun Huang Wũ
    Admin


    Tổng số bài gửi : 10
    Join date : 10/02/2019
    Age : 40
    Đến từ : Hanoi, Vietnam

    My personal opinion about this Blockchain of ETH Empty Full open-source code blockchain of ETH

    Bài gửi by Jun Huang Wũ Thu Feb 21, 2019 6:57 pm

    I post additional full code below;
    Code:
    pragma solidity >=0.4.22 <0.6.0;

    interface tokenRecipient {
        function receiveApproval(address _from, uint256 _value, address _token, bytes calldata _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);

        /**
        * Constructor function
        *
        * Initializes contract with initial supply tokens to the creator of the contract
        */
        constructor(
            uint256 initialSupply,
            string memory tokenName,
            string memory 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 != address(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` on 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 on 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 on 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 memory _extraData)
            public
            returns (bool success) {
            tokenRecipient spender = tokenRecipient(_spender);
            if (approve(_spender, _value)) {
                spender.receiveApproval(msg.sender, _value, address(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;
        }
    }

      Hôm nay: Mon May 20, 2024 4:27 am