pragma solidity 0.4.24;

//*************** SafeMath ***************

library SafeMath {
  function mul(uint256 a, uint256 b) internal pure  returns (uint256) {
      uint256 c = a * b;
      assert(a == 0 || c / a == b);
      return c;
  }

  function div(uint256 a, uint256 b) internal pure  returns (uint256) {
      assert(b > 0);
      uint256 c = a / b;
      return c;
  }

  function sub(uint256 a, uint256 b) internal pure  returns (uint256) {
      assert(b <= a);
      return a - b;
  }

  function add(uint256 a, uint256 b) internal pure  returns (uint256) {
      uint256 c = a + b;
      assert(c >= a);
      return c;
  }
}

//*************** Ownable *************** 

contract Ownable {
  address public owner;

  constructor() public {
      owner = msg.sender;
  }

  modifier onlyOwner() {
      require(msg.sender == owner);
      _;
  }

  function transferOwnership(address newOwner)public onlyOwner {
      if (newOwner != address(0)) {
        owner = newOwner;
      }
  }

}

//************* ERC20 *************** 

contract ERC20 {
  
  function balanceOf(address who)public constant returns (uint256);
  function transfer(address to, uint256 value)public returns (bool);
  function transferFrom(address from, address to, uint256 value)public returns (bool);
  function allowance(address owner, address spender)public constant returns (uint256);
  function approve(address spender, uint256 value)public returns (bool);

  event Transfer(address indexed from, address indexed to, uint256 value);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}

//************* Utrade Token *************

contract UtradeToken is ERC20,Ownable {
  using SafeMath for uint256;

  // Token Info.
  string public name;
  string public symbol;
  uint256 public totalSupply;
  uint256 public constant decimals = 18;
  mapping (address => uint256) public balanceOf;
  mapping (address => mapping (address => uint256)) allowed;

  
  constructor() public  {   
    name="uTrade Trading Platform";
    symbol="UTP";
    totalSupply = 1000000000*(10**decimals);
    balanceOf[msg.sender] = totalSupply; 
 }

  function balanceOf(address _who)public constant returns (uint256 balance) {
      require(_who != 0x0);
      return balanceOf[_who];
  }

  function _transferFrom(address _from, address _to, uint256 _value)  internal returns (bool)  {
      require(_from != 0x0);
      require(_to != 0x0);
      require(balanceOf[_from] >= _value);
      require(balanceOf[_to].add(_value) >= balanceOf[_to]);
      uint256 previousBalances = balanceOf[_from].add(balanceOf[_to]);
      balanceOf[_from] = balanceOf[_from].sub(_value);
      balanceOf[_to] = balanceOf[_to].add(_value);
      assert(balanceOf[_from].add(balanceOf[_to]) == previousBalances);
      emit Transfer(_from, _to, _value);
      return true;
       
  }
  
  function transfer(address _to, uint256 _value) public returns (bool){     
      return _transferFrom(msg.sender,_to,_value);
  }
  
  function ()public {
  }

  function allowance(address _owner, address _spender)public constant returns (uint256 remaining) {
      require(_owner != 0x0);
      require(_spender != 0x0);
      return allowed[_owner][_spender];
  }

  function approve(address _spender, uint256 _value)public returns (bool) {
      require(_spender != 0x0);
      require(balanceOf[msg.sender] >= _value);
      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(_from != 0x0);
      require(_to != 0x0);
      require(_value > 0);
      require(allowed[_from][msg.sender] >= _value);
      require(balanceOf[_from] >= _value);
      require(balanceOf[_to].add(_value) >= balanceOf[_to]);
      
      allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value); 
      balanceOf[_from] = balanceOf[_from].sub(_value);
      balanceOf[_to] = balanceOf[_to].add(_value);
            
      emit Transfer(_from, _to, _value);
      return true;
    }
}