以太坊钱包发币教程(学习如何使用以太坊钱包创建自己的代币)

pragma solidity ^0.4.16;

interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) public; }

contract MyToken {

// Public variables of the token

string public name;

string public symbol;

uint8 public decimals = 18;

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);

/**

* Constrctor function

*

* Initializes contract with initial supply tokens to the creator of the contract

*/

function MyToken(

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 {

_transfer(msg.sender, _to, _value);

}

/**

* 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;

}

}