Find the first character that is not whitespace in a std::string

Question

Lets say I have

std::wstring str(L"   abc");

The contents of the string could be arbitrary.

How can I find the first character that is not whitespace in that string, i.e. in this case the position of the 'a'?

Answer 1

use [std::basic_string::find_first_not_of][1] function

std::wstring::size_type pos = str.find_first_not_of(' ');

pos is 3

Update: to find any other chars

const wstring delims(L" \t,.;");
std::wstring::size_type pos = str.find_first_not_of(delims);