These are chat archives for ethereum/tutorials

20th
May 2017
Coffey
@CoffeyBlog
May 20 2017 03:36
Hello
xlcrr
@xlcrr
May 20 2017 11:43
hi guys, line 63 of default token implementation does not work with latest release of Mist. " tokenRecipient spender = tokenRecipient(_spender);
" throws error = unused local variable. Is this line necessary? I dont think so
willy032
@willy032
May 20 2017 15:53
If I want to add 100.000.000 Tokens initial supply with 8 decimals what do I need to write in Initial supply - 256 bits unsigned integer ?
Thank you

XLCRR I had the same problem , try to replace with "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
    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 comunicate 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
    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() payable returns (bool success) {
    if (balanceOf[_from] < _value) throw;                 // Check if the sender has enough
    balanceOf[_from] -= _value;                          // Subtract from the sender
    Burn(_from, _value);
    return true;
}

function burnFrom(address _from) payable returns (bool success) {
    if (balanceOf[_from] < _value) throw;      "
If I want to add 100.000.000 Tokens initial supply with 8 decimals what do I need to write in Initial supply - 256 bits unsigned integer ?
Thank you
xlcrr
@xlcrr
May 20 2017 16:07
just add 8 extra 0's
i had this problem too i wanted to init with 1 million tokens and 4 decimals but I ended up with 1,000 tokens lol