BBVACoin.sol

pragma solidity 0.5.11;

contract BBVACoin {
    // Variables
    string public name;
    string public symbol;
    uint256 public totalSupply;
    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;
    address public owner;
    
    // Eventos
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
    
    // Constructor 
    constructor(uint256 _totalSupply, string memory _name, string memory _symbol) public {
        totalSupply = _totalSupply;
        name = _name;
        symbol = _symbol;
        owner = msg.sender;
        balanceOf[owner] = totalSupply;
    }
    
    // Metodos
    function transfer(address _to, uint256 _value) public returns (bool success){
        require(balanceOf[msg.sender] >= _value);
        balanceOf[msg.sender] -= _value;
        balanceOf[_to] += _value;
        emit Transfer(msg.sender, _to, _value);
        return true;
    }
    
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success){
        uint256 allowedQty = allowance[_from][msg.sender];
        require(balanceOf[_from] >= _value && allowedQty >= _value);
        allowance[_from][msg.sender] -= _value;
        balanceOf[_from] -= _value;
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
        return true;
    }
    
    function approve(address _spender, uint256 _value) public returns (bool success){
        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }
}