I am new to boost Libraries and I am trying to find a substring using Boost::Regex
Lets say I want to find string "Hello" in "Hello world".
std::string completeStr = "Hello World"; std::string::const_iterator startOffset = completeStr.begin(); std::string::const_iterator endOffset = completeStr.end();
std::string searchWord= "Hello"; boost::regex expression(searchWord);
boost::match_flag_type flags = boost::match_any; while(boost::regex_search(startOffset, endOffset, what, expression, flags)) { int32 position = what.position(1); int32 len = what[1].length(); }
but value of this position and length value is coming out to be -1. It is not able to find this substring, Could anyone tell me what I am doing wrong ?
First off, you don't need to use "match_any" unless it's what you really mean. You're then accessing *marked subexpression 1* inside the loop, but the regular expression *does not contain any marked subexpressions*. Use what.position() and what.length() to access the position and length info of the match as a whole. HTH, John.