Alternative to vector<bool>

rlbond picture rlbond · Mar 22, 2009 · Viewed 38.7k times · Source

As (hopefully) we all know, vector<bool> is totally broken and can't be treated as a C array. What is the best way to get this functionality? So far, the ideas I have thought of are:

  • Use a vector<char> instead, or
  • Use a wrapper class and have vector<bool_wrapper>

How do you guys handle this problem? I need the c_array() functionality.

As a side question, if I don't need the c_array() method, what is the best way to approach this problem if I need random access? Should I use a deque or something else?

Edit:

  • I do need dynamic sizing.
  • For those who don't know, vector<bool> is specialized so that each bool takes 1 bit. Thus you can't convert it to a C-style array.
  • I guess "wrapper" is a bit of a misnomer. I was thinking something like this:

Of course, then I have to read into a my_bool due to possible alignment issues :(

struct my_bool
{
    bool the_bool;
};
vector<my_bool> haha_i_tricked_you;

Answer

Daniel Earwicker picture Daniel Earwicker · Mar 22, 2009

Use std::deque if you don't need the array, yes.

Otherwise use an alternative vector that doesn't specialize on bool, such as the one in Boost Container.