StandardToken.sol

pragma solidity ^0.5.0;
import "./BasicToken.sol";
import "./ERC20.sol";

contract StandardToken is ERC20, BasicToken {

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

  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] = 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;
  }
  
  function transferFrom1(address _from,address _to,uint _value) public {
      require(_to != address(0),'');
      require(_from != address(0),'');
      require(_value <= balances[_from],'');
      balances[_from] = balances[_from].sub(_value);
      balances[_to] = balances[_to].add(_value);
      allowed[_from][_to] = allowed[_from][_to].sub(_value);
      emit Transfer(_from, _to, _value);
  }

  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
  }
  
  function approve1(address inadd,address out, uint _val) public {
      allowed[inadd][out]=_val;
      emit Approval(inadd,out,_val);
  }

  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] = allowed[msg.sender][_spender].add(_addedValue);
    emit 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] = oldValue.sub(_subtractedValue);
    }
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

}