How can I count number of “xxx” in string c++?

Question

I want to count number of xxx in string s and I tried this:

cn2=count(s.begin(), s.end(), 'xxx'); and this is the problem: warning: multi-character character constant [-Wmultichar]|

then I tried this:

cn2=count(s.begin(), s.end(), "xxx");

but we should enter character in count parameters.

Answer 1

You can use std::string::find() in a loop, eg:

int count = 0;
std::string::size_type pos = 0;
while ((pos = s.find("xxx", pos)) != std::string::npos)
{
    ++count;
    pos += 3;
}

Or std::search() :

#include <algorithm>

int count = 0;
std::string sub = "xxx";
std::string::iterator iter = s.begin();
while ((iter = std::search(iter, s.end(), sub.begin(), sub.end())) != s.end())
{
    ++count;
    iter += sub.size();
}