solidity/std/StandardToken

import "./Token";

contract StandardToken is Token {
	uint256 tokenSupply;
	mapping (address => uint256) balances;
	mapping (address =>
		mapping (address => uint256)) approvedTransfers;

	function StandardToken(address _initialOwner, uint256 _supply) {
		tokenSupply = _supply;
		balances[_initialOwner] = _supply;
	}

	function totalSupply() constant returns (uint256 supply) {
		return tokenSupply;
	}

	function balanceOf(address _owner) constant returns (uint256 balance) {
		return balances[_owner];
	}

	function transfer(address _to, uint256 _value) returns (bool success) {
		if (balances[msg.sender] >= _value) {
			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) {
		if (approvedTransfers[_from][msg.sender] >= _value) {
			approvedTransfers[_from][msg.sender] -= _value;
			balances[_to] += _value;
			Transfer(_from, _to, _value);
			return true;
		}
		else {
			return false;
		}
	}

	function approve(address _spender, uint256 _value) returns (bool success) {
		approvedTransfers[msg.sender][_spender] = _value;
		Approval(msg.sender, _spender, _value);
		return true;
	}

	function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
		return approvedTransfers[_owner][_spender];
	}
}