pragma solidity ^0.4.13;

interface ERC20 {
    // Get the total token supply
    function totalSupply() constant returns (uint totalSupply);
    // Get the account balance of another account with address _owner
    function balanceOf(address _owner) constant returns (uint balance);
    // Send _value amount of tokens to address _to
    function transfer(address _to, uint _value) returns (bool success);
    // Send _value amount of tokens from address _from to address _to
    function transferFrom(address _from, address _to, uint _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, uint _value) returns (bool success);
    // Returns the amount which _spender is still allowed to withdraw from _owner
    function allowance(address _owner, address _spender) constant returns (uint remaining);
    // Triggered when tokens are transferred.
    event Transfer(address indexed _from, address indexed _to, uint _value);
    // Triggered whenever approve(address _spender, uint256 _value) is called.
    event Approval(address indexed _owner, address indexed _spender, uint _value);
}

contract NewPiedPiperCoin is ERC20 {
  using SafeMath for uint;
     
    string internal _name;
    string internal _symbol;
    uint8 internal _decimals;
    uint256 internal _totalSupply;

    mapping (address => uint256) internal balances;
    mapping (address => mapping (address => uint256)) internal allowed;

    function NewPiedPiperCoin(string name, string symbol, uint8 decimals, uint256 totalSupply) public {
        _symbol = symbol;
        _name = name;
        _decimals = decimals;
        _totalSupply = totalSupply;
        balances[msg.sender] = totalSupply;
    }

    function name()
        public
        view
        returns (string) {
        return _name;
    }

    function symbol()
        public
        view
        returns (string) {
        return _symbol;
    }

    function decimals()
        public
        view
        returns (uint8) {
        return _decimals;
    }

    function totalSupply()
        public
        view
        returns (uint256) {
        return _totalSupply;
    }

   function transfer(address _to, uint256 _value) public returns (bool) {
     require(_to != address(0));
     require(_value <= balances[msg.sender]);
     balances[msg.sender] = SafeMath.sub(balances[msg.sender], _value);
     balances[_to] = SafeMath.add(balances[_to], _value);
     Transfer(msg.sender, _to, _value);
     return true;
   }

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

  function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));
     require(_value <= balances[_from]);
     require(_value <= allowed[_from][msg.sender]);

    balances[_from] = SafeMath.sub(balances[_from], _value);
     balances[_to] = SafeMath.add(balances[_to], _value);
     allowed[_from][msg.sender] = SafeMath.sub(allowed[_from][msg.sender], _value);
    Transfer(_from, _to, _value);
     return true;
   }

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

  function allowance(address _owner, address _spender) public view returns (uint256) {
     return allowed[_owner][_spender];
   }

   function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
     allowed[msg.sender][_spender] = SafeMath.add(allowed[msg.sender][_spender], _addedValue);
     Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
     return true;
   }

  function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
     uint oldValue = allowed[msg.sender][_spender];
     if (_subtractedValue > oldValue) {
       allowed[msg.sender][_spender] = 0;
     } else {
       allowed[msg.sender][_spender] = SafeMath.sub(oldValue, _subtractedValue);
    }
     Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
     return true;
   }

}

library SafeMath {
  function mul(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal constant returns (uint256) {
    assert(b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = a / b;
    assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return c;
  }

  function sub(uint256 a, uint256 b) internal constant returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}