[PATCH] Refactoring based on cppcheck suggestions

[José Abílio Matos]

On Monday, October 5, 2020 1:52:19 PM WEST Jean-Marc Lasgouttes wrote:
> C++ stl uses unsigned for vector indices.
> 
> JMarc

What the *man* has to say about that (pag. 123 from the article below):

" The most contentious part of getting span into C++20 turned out to be the 
type of subscripts and sizes. The Core Guidelines span::size() was defined to 
return a signed int as opposed to the unsigned used by the standard-library 
containers. Similarly, subscripts were ints like for arrays, rather than 
unsigned as they are for standard-library containers. This led to a revival of 
an old and contentious issue:
• Some consider it obvious that subscripts, being non-negative, should be 
represented as unsigned.
• Some consider consistency with standard-library containers more important 
than any arguments about past mistakes related to unsigned.
• Some consider the use of unsigned to represent non-negative numbers 
misguided (giving a false sense of safety) and a significant source of errors.

Over the strenuous objections of the original designers (including me) and 
implementers of span, the second group won the votes, enthusiastically 
supported by the first group, so std::span has unsigned sizes and subscripts. 
I consider that a sad failure to take advantage of a rare opportunity to 
remedy a nasty old mistake [Stroustrup 2018e]. Somewhat predictably and not 
irrationally, the committee chose bug compatibility over the work of removing 
a significant bug source.
But what could be wrong about representing subscripts as unsigned? This 
appears to be a rather emotional topic. I received several hate mails about 
this. There are two fundamental problems:
• unsigned does not model natural numbers: it has modular arithmetic and 
subtraction. For example, if ch is an unsigned char, ch+100 will never 
overflow.
• int and unsigned convert to each other at the slightest provocation, turning 
negative values into huge signed values and vice versa. For example, -2<2u is 
false; 2u is unsigned, so -2 is converted into a huge positive integer before 
the comparison."

Thriving in a Crowded and Changing World: C++ 2006–2020
Bjarne Stroustrup
Proc. ACM Program. Lang., Vol. 4, No. HOPL, Article 70. 

-- 
José Abílio