pragma solidity ^0.4.8;
 
// ----------------------------------------------------------------------------------------------
// Sample fixed supply token contract
// Enjoy. (c) BokkyPooBah 2017. The MIT Licence.
// ----------------------------------------------------------------------------------------------
 
 // ERC Token Standard #20 Interface
// https://github.com/ethereum/EIPs/issues/20
contract ERC20Interface {
// Get the total token supply
function totalSupply() constant returns (uint256 totalSupply);

// Get the account balance of another account with address _owner
function balanceOf(address _owner) constant returns (uint256 balance);

// Send _value amount of tokens to address _to
function transfer(address _to, uint256 _value) returns (bool success);

// Send _value amount of tokens from address _from to address _to
function transferFrom(address _from, address _to, uint256 _value) returns (bool success);

// Allow _spender to withdraw from your account, multiple times, up to the _value amount.
// If this function is called again it overwrites the current allowance with _value.
// this function is required for some DEX functionality
function approve(address _spender, uint256 _value) returns (bool success);

// Returns the amount which _spender is still allowed to withdraw from _owner
function allowance(address _owner, address _spender) constant returns (uint256 remaining);

// Triggered when tokens are transferred.
event Transfer(address indexed _from, address indexed _to, uint256 _value);

// Triggered whenever approve(address _spender, uint256 _value) is called.
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}
 
contract FixedSupplyToken is ERC20Interface {
string public constant symbol = "ATS";
string public constant name = "Authorship Token";
uint8 public constant decimals = 4;
uint256 _totalSupply = 1000000000000;

 // Owner of this contract
address public owner;

// Balances for each account
mapping(address => uint256) balances;

// Owner of account approves the transfer of an amount to another account
mapping(address => mapping (address => uint256)) allowed;

 // Functions with this modifier can only be executed by the owner
modifier onlyOwner() {
if (msg.sender != owner) {
     throw;
 }
   _;
}

// Constructor
 function FixedSupplyToken() {
    owner = msg.sender;
     balances[owner] = _totalSupply;
 }

function totalSupply() constant returns (uint256 totalSupply) {
      totalSupply = _totalSupply;
}

// What is the balance of a particular account?
function balanceOf(address _owner) constant returns (uint256 balance) {
    return balances[_owner];
}

// Transfer the balance from owner's account to another account
function transfer(address _to, uint256 _amount) returns (bool success) {
if (balances[msg.sender] >= _amount 
&& _amount > 0
&& balances[_to] + _amount > balances[_to]) {
balances[msg.sender] -= _amount;
balances[_to] += _amount;
Transfer(msg.sender, _to, _amount);
return true;
} else {
return false;
}
}

// Send _value amount of tokens from address _from to address _to
// The transferFrom method is used for a withdraw workflow, allowing contracts to send
// tokens on your behalf, for example to "deposit" to a contract address and/or to charge
// fees in sub-currencies; the command should fail unless the _from account has
// deliberately authorized the sender of the message via some mechanism; we propose
// these standardized APIs for approval:
function transferFrom(
address _from,
address _to,
uint256 _amount
) returns (bool success) {
if (balances[_from] >= _amount
&& allowed[_from][msg.sender] >= _amount
&& _amount > 0
&& balances[_to] + _amount > balances[_to]) {
 balances[_from] -= _amount;
allowed[_from][msg.sender] -= _amount;
balances[_to] += _amount;
Transfer(_from, _to, _amount);
return true;
} else {
return false;
}
}

// Allow _spender to withdraw from your account, multiple times, up to the _value amount.
 // If this function is called again it overwrites the current allowance with _value.
function approve(address _spender, uint256 _amount) returns (bool success) {
allowed[msg.sender][_spender] = _amount;
Approval(msg.sender, _spender, _amount);
return true;
}

function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
return allowed[_owner][_spender];
}
}