在乙太坊錢包上創建合約時出錯

首先，我想提供一個免責聲明。我不是開發人員，我從 14 歲起就從未研究過程式碼，也從未編寫過腳本。我正在為我目前工作的公司做這個項目，當我試圖通過乙太坊創建一個令牌時，我經常收到這個錯誤：

"throw" is deprecated in favour of "revert()", "require()" and "assert()".
       if (_to == 0x0) throw;                               
// Prevent transfer to 0x0 address. Use burn() instead
                       ^---^, 

每次我輸入乙太坊提供的程式碼時都會彈出這個錯誤，他們的模板。我不知道為什麼會發生這種情況，也不知道如何解決它。我在網上到處找，但我似乎找不到其他人面臨同樣的問題。我該如何解決？我做錯了嗎？這是我第一次嘗試在伺服器上而不是在測試網上部署合約。先感謝您！

這是程式碼：

pragma solidity ^0.4.8;
contract tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData); }

contract MyToken {
/* Public variables of the token */
string public standard = 'Token 0.1';
string public name;
string public symbol;
uint8 public decimals;
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 notifies clients about the amount burnt */
event Burn(address indexed from, uint256 value);

/* Initializes contract with initial supply tokens to the creator of the contract */
function MyToken(
   uint256 initialSupply,
   string tokenName,
   uint8 decimalUnits,
   string tokenSymbol
   ) {
   balanceOf[msg.sender] = initialSupply;              // Give the creator all initial tokens
   totalSupply = initialSupply;                        // Update total supply
   name = tokenName;                                   // Set the name for display purposes
   symbol = tokenSymbol;                               // Set the symbol for display purposes
   decimals = decimalUnits;                            // Amount of decimals for display purposes
}

/* Send coins */
function transfer(address _to, uint256 _value) {
   if (_to == 0x0) throw;                               // Prevent transfer to 0x0 address. Use burn() instead
   if (balanceOf[msg.sender] < _value) throw;           // Check if the sender has enough
   if (balanceOf[_to] + _value < balanceOf[_to]) throw; // Check for overflows
   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;
   return true;
}

/* Approve and then communicate the approved contract in a single tx */
function approveAndCall(address _spender, uint256 _value, bytes _extraData)
   returns (bool success) {
   tokenRecipient spender = tokenRecipient(_spender);
   if (approve(_spender, _value)) {
       spender.receiveApproval(msg.sender, _value, this, _extraData);
       return true;
   }
}        

/* A contract attempts to get the coins */
function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {
   if (_to == 0x0) throw;                                // Prevent transfer to 0x0 address. Use burn() instead
   if (balanceOf[_from] < _value) throw;                 // Check if the sender has enough
   if (balanceOf[_to] + _value < balanceOf[_to]) throw;  // Check for overflows
   if (_value > allowance[_from][msg.sender]) throw;     // Check allowance
   balanceOf[_from] -= _value;                           // Subtract from the sender
   balanceOf[_to] += _value;                             // Add the same to the recipient
   allowance[_from][msg.sender] -= _value;
   Transfer(_from, _to, _value);
   return true;
}

function burn(uint256 _value) returns (bool success) {
   if (balanceOf[msg.sender] < _value) throw;            // Check if the sender has enough
   balanceOf[msg.sender] -= _value;                      // Subtract from the sender
   totalSupply -= _value;                                // Updates totalSupply
   Burn(msg.sender, _value);
   return true;
}

function burnFrom(address _from, uint256 _value) returns (bool success) {
   if (balanceOf[_from] < _value) throw;                // Check if the sender has enough
   if (_value > allowance[_from][msg.sender]) throw;    // Check allowance
   balanceOf[_from] -= _value;                          // Subtract from the sender
   totalSupply -= _value;                               // Updates totalSupply
   Burn(_from, _value);
   return true;
}

}

程式碼來自ethereum.org 令牌範例

throw在 Solidity 版本0.4.13中已棄用。您需要將每行替換if(condition) throw;為require(opposite of condition);. 例如：

if (_to == 0x0) throw;

變成

require(_to != 0x0);

throw在整個程式碼中多次使用，您需要更改每一個

所以它將是這個：

   /* Send coins */
function transfer(address _to, uint256 _value) {
   require (_to != 0x0) ;                               // Prevent transfer to 0x0 address. Use burn() instead
   if (balanceOf[msg.sender] < _value);           // Check if the sender has enough
   if (balanceOf[_to] + _value < balanceOf[_to]); // Check for overflows
   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
}

或者：

   /* Send coins */
function transfer(address _to, uint256 _value) {
   require (_to != 0x0) ;                               // Prevent transfer to 0x0 address. Use burn() instead
   if (balanceOf[msg.sender] < _value) require;           // Check if the sender has enough
   if (balanceOf[_to] + _value < balanceOf[_to]) require; // Check for overflows
   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
}

.. if () 要求；還是沒有？

引用自：https://ethereum.stackexchange.com/questions/23018