SOCK Token (STOC) is a ERC20 Token

SToken.sol

pragma solidity ^0.4.11;
import './IERC20.sol';
contract SToken is IERC20{
    
    uint public constant _totalSupply = 100000000;
    string public constant symbol = "STOC";
    string public constant name = "SOCK TOKEN";
    uint8 public constant decimals = 3;
    mapping(address => uint256) balances;
    mapping(address => mapping(address => uint256)) allowed;
    function SToken(){
        balances[msg.sender] = _totalSupply;
    }
    function totalSupply() constant returns (uint256 totalSupply){
        return _totalSupply;
    }

    function balanceOf(address _owner) constant returns (uint256 balance){
        return balances[_owner];
    }
    function transfer(address _to, uint256 _value) returns (bool success){
        require(
            balances[msg.sender] >= _value
            && _value > 0
            );
            balances[msg.sender] -= _value;
            balances[_to] += _value;
            Transfer (msg.sender,_to,_value);
            return true;
    }
    function transferFrom(address _from, address _to, uint256 _value) returns (bool success){
        require(
            allowed[_from][msg.sender] >= _value
            && balances[_from] >= _value
            && _value > 0
            );
            balances[_from] -= _value;
            balances[_to] += _value;
            allowed[_from][msg.sender] -= _value;
            Transfer(_from,_to,_value);
            return true;
    }
    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];
    }
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
    
    
}