Trimming white spaces/converting iterators
I wanted to write two one-line functions which will trim white spaces from left and right side of a string. Left side weren't problem:
void trimLeft(string &s) {
s.erase(s.begin(), find_if(s.begin(), s.end(), (int (*)(int))isgraph));
}
But when I tried someth开发者_StackOverflowing similar for right side:
void trimRight(string &s) {
s.erase(find_if(s.rbegin(), s.rend(), (int (*)(int))isgraph), s.end());
}
I had some compiler errors. The problem is that I must convert reverse_iterator (which is returned by find_if) to normal iterator. How to do this?
You can use the base()
member function to recover the underlying iterator from its reverse_iterator.
void trimRight(string &s) {
s.erase(find_if(s.rbegin(), s.rend(), (int (*)(int))isgraph).base(), s.end());
}
Looking at the documentation, it seems like string::erase should take reverse_iterators just fine. The problem is that you're mixing reverse and forward iterators. So try
void trimRight(string &s) {
s.erase(s.rbegin(), find_if(s.rbegin(), s.rend(), (int (*)(int))isgraph));
}
Edit: Nope.
Use boost::trim?
http://www.boost.org/doc/libs/1_47_0/doc/html/string_algo/usage.html#id2895820
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