pragma solidity ^0.4.24;

library SafeMath {
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    if (a == 0) {
      return 0;
    }

    uint256 c = a * b;
    require(c / a == b);

    return c;
  }

  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b > 0); 
    uint256 c = a / b;
    return c;
  }

  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b <= a);
    uint256 c = a - b;

    return c;
  }

  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    require(c >= a);

    return c;
  }

  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b != 0);
    return a % b;
  }
}

interface IERC20 {
  function totalSupply() external view returns (uint256);

  function balanceOf(address who) external view returns (uint256);

  function allowance(address owner, address spender)
    external view returns (uint256);

  function transfer(address to, uint256 value) external returns (bool);

  function approve(address spender, uint256 value)
    external returns (bool);

  function transferFrom(address from, address to, uint256 value)
    external returns (bool);

  event Transfer(
    address indexed from,
    address indexed to,
    uint256 value
  );

  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

contract TPRToken is IERC20 {
  using SafeMath for uint256;

  mapping (address => uint256) private _balances;

  mapping (address => mapping (address => uint256)) private _allowed;

  uint256 private _totalSupply;
  
  string public name = "Tripair Token";
  string public symbol = "TPR";
  uint public decimals = 4;
  uint public totalSupply = 100000000 * 10 ** decimals;
 
  constructor (address admin_) public {
      _balances[admin_] = totalSupply;
  }

  function totalSupply() public view returns (uint256) {
    return _totalSupply;
  }

  function balanceOf(address owner) public view returns (uint256) {
    return _balances[owner];
  }

  function allowance(
    address owner,
    address spender
   )
    public
    view
    returns (uint256)
  {
    return _allowed[owner][spender];
  }

  function transfer(address to, uint256 value) public returns (bool) {
    require(value <= _balances[msg.sender]);
    require(to != address(0));

    _balances[msg.sender] = _balances[msg.sender].sub(value);
    _balances[to] = _balances[to].add(value);
    emit Transfer(msg.sender, to, value);
    return true;
  }

  function approve(address spender, uint256 value) public returns (bool) {
    require(spender != address(0));

    _allowed[msg.sender][spender] = value;
    emit Approval(msg.sender, spender, value);
    return true;
  }

  function transferFrom(
    address from,
    address to,
    uint256 value
  )
    public
    returns (bool)
  {
    require(value <= _balances[from]);
    require(value <= _allowed[from][msg.sender]);
    require(to != address(0));

    _balances[from] = _balances[from].sub(value);
    _balances[to] = _balances[to].add(value);
    _allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
    emit Transfer(from, to, value);
    return true;
  }
}