“Usando para la solidez” Código de respuesta

Usando para la solidez

// `for` is used to attach functions to variable types.

// Example:
function sum(uint a, uint b) returns(uint) {
  return a + b;
}

using sum for uint;

// then you can use this inside your contracts:
contract MyContract {
  function add1(uint num) public pure returns(uint) {
    return num.sum(1);
    // `num` is passed as the first parameter (`a`) and `1` as the second (`b`)
  }
}

// You can also use libraries this way:

library Math {
  function sum(uint a, uint b) returns(uint) {
    return a + b;
  }
  
  function sub1(uint x) returns(uint) {
    return(x - 1);
  }
}

contract MyContract {
  using Math for uint;
  
  function uselessCalculation(uint x, uint y) returns(uint) {
  	return x.sum(y).sub1();
  }
  
}