Created
November 27, 2018 23:13
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Smart contract for ERC 20 easy creation
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pragma solidity ^0.4.24; | |
contract Token { | |
/// @return total amount of tokens | |
function totalSupply() constant returns (uint256 supply) {} | |
/// @param _owner The address from which the balance will be retrieved | |
/// @return The balance | |
function balanceOf(address _owner) constant returns (uint256 balance) {} | |
/// @notice send `_value` token to `_to` from `msg.sender` | |
/// @param _to The address of the recipient | |
/// @param _value The amount of token to be transferred | |
/// @return Whether the transfer was successful or not | |
function transfer(address _to, uint256 _value) returns (bool success) {} | |
/// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from` | |
/// @param _from The address of the sender | |
/// @param _to The address of the recipient | |
/// @param _value The amount of token to be transferred | |
/// @return Whether the transfer was successful or not | |
function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {} | |
/// @notice `msg.sender` approves `_addr` to spend `_value` tokens | |
/// @param _spender The address of the account able to transfer the tokens | |
/// @param _value The amount of wei to be approved for transfer | |
/// @return Whether the approval was successful or not | |
function approve(address _spender, uint256 _value) returns (bool success) {} | |
/// @param _owner The address of the account owning tokens | |
/// @param _spender The address of the account able to transfer the tokens | |
/// @return Amount of remaining tokens allowed to spent | |
function allowance(address _owner, address _spender) constant returns (uint256 remaining) {} | |
event Transfer(address indexed _from, address indexed _to, uint256 _value); | |
event Approval(address indexed _owner, address indexed _spender, uint256 _value); | |
} | |
contract StandardToken is Token { | |
function transfer(address _to, uint256 _value) returns (bool success) { | |
//Default assumes totalSupply can't be over max (2^256 - 1). | |
//If your token leaves out totalSupply and can issue more tokens as time goes on, you need to check if it doesn't wrap. | |
//Replace the if with this one instead. | |
//if (balances[msg.sender] >= _value && balances[_to] + _value > balances[_to]) { | |
if (balances[msg.sender] >= _value && _value > 0) { | |
balances[msg.sender] -= _value; | |
balances[_to] += _value; | |
Transfer(msg.sender, _to, _value); | |
return true; | |
} else { return false; } | |
} | |
function transferFrom(address _from, address _to, uint256 _value) returns (bool success) { | |
//same as above. Replace this line with the following if you want to protect against wrapping uints. | |
//if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && balances[_to] + _value > balances[_to]) { | |
if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && _value > 0) { | |
balances[_to] += _value; | |
balances[_from] -= _value; | |
allowed[_from][msg.sender] -= _value; | |
Transfer(_from, _to, _value); | |
return true; | |
} else { return false; } | |
} | |
function balanceOf(address _owner) constant returns (uint256 balance) { | |
return balances[_owner]; | |
} | |
function approve(address _spender, uint256 _value) returns (bool success) { | |
allowed[msg.sender][_spender] = _value; | |
Approval(msg.sender, _spender, _value); | |
return true; | |
} | |
function allowance(address _owner, address _spender) constant returns (uint256 remaining) { | |
return allowed[_owner][_spender]; | |
} | |
mapping (address => uint256) balances; | |
mapping (address => mapping (address => uint256)) allowed; | |
uint256 public totalSupply; | |
} | |
//name this contract whatever you'd like | |
contract ERC20Token is StandardToken { | |
function () { | |
//if ether is sent to this address, send it back. | |
throw; | |
} | |
/* Public variables of the token */ | |
/* | |
NOTE: | |
The following variables are OPTIONAL vanities. One does not have to include them. | |
They allow one to customise the token contract & in no way influences the core functionality. | |
Some wallets/interfaces might not even bother to look at this information. | |
*/ | |
string public name; //fancy name: eg Simon Bucks | |
uint8 public decimals; //How many decimals to show. ie. There could 1000 base units with 3 decimals. Meaning 0.980 SBX = 980 base units. It's like comparing 1 wei to 1 ether. | |
string public symbol; //An identifier: eg SBX | |
string public version = 'H1.0'; //human 0.1 standard. Just an arbitrary versioning scheme. | |
// | |
// CHANGE THESE VALUES FOR YOUR TOKEN | |
// | |
//make sure this function name matches the contract name above. So if you're token is called TutorialToken, make sure the //contract name above is also TutorialToken instead of ERC20Token | |
function ERC20Token( | |
) { | |
balances[msg.sender] = 100000000000000000000000000; // Give the creator all initial tokens (100000 for example) | |
totalSupply = 100000000000000000000000000; // Update total supply (100000 for example) | |
name = "My Token"; // Set the name for display purposes | |
decimals = 18; // Amount of decimals for display purposes | |
symbol = "MTK"; // Set the symbol for display purposes | |
} | |
/* Approves and then calls the receiving contract */ | |
function approveAndCall(address _spender, uint256 _value, bytes _extraData) returns (bool success) { | |
allowed[msg.sender][_spender] = _value; | |
Approval(msg.sender, _spender, _value); | |
//call the receiveApproval function on the contract you want to be notified. This crafts the function signature manually so one doesn't have to include a contract in here just for this. | |
//receiveApproval(address _from, uint256 _value, address _tokenContract, bytes _extraData) | |
//it is assumed that when does this that the call *should* succeed, otherwise one would use vanilla approve instead. | |
if(!_spender.call(bytes4(bytes32(sha3("receiveApproval(address,uint256,address,bytes)"))), msg.sender, _value, this, _extraData)) { throw; } | |
return true; | |
} | |
} |
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