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--- docs:programming:cpp:boost:regex_example [2009/02/11 22:28] – created billh
+++ docs:programming:cpp:boost:regex_example [2009/02/14 12:56] (current) – billh
@@ Line 24: / Line 24: @@
 	}
+	return 0;
+}
+</code>
+===== sub-expression match =====
+A sub-expression match retains the components specified in parethesis () for later use.
+<code cpp>
+#include <string>
+#include <iostream>
+#include <boost/regex.hpp>
+int main(int argc, char* argv[]){
+	std::string input;
+	if(argc > 1){
+		input = argv[1];
+	}else{
+		std::cin >> input;
+	}
+	// note that an escape slash \ needs escaped itself
+	boost::regex email("^([^@]+)@([^@]+)\\.([^.]+)$");
+	boost::cmatch what;
+	if( regex_match(input.c_str(), what, email) ){
+		std::cout << "Matched OK" << std::endl;
+		std::cout << "Account Name: " << what[1] << std::endl;
+		std::cout << "Computer Name/Subdomain: " << what[2] << std::endl;
+		std::cout << "Domain: " << what[3] << std::endl;
+	}else{
+		std::cout << "No match" << std::endl;
+	}
 	return 0;
 }