Tutorial by Examples

const auto input = "Some people, when confronted with a problem, think \"I know, I'll use regular expressions.\""s; smatch sm; cout << input << endl; // If input ends in a quotation that contains a word that begins with "reg" and another word begining...

This code takes in various brace styles and converts them to One True Brace Style: const auto input = "if (KnR)\n\tfoo();\nif (spaces) {\n foo();\n}\nif (allman)\n{\n\tfoo();\n}\nif (horstmann)\n{\tfoo();\n}\nif (pico)\n{\tfoo(); }\nif (whitesmiths)\n\t{\n\tfoo();\n\t}\n"s; cout &lt...

A std::regex_token_iterator provides a tremendous tool for extracting elements of a Comma Separated Value file. Aside from the advantages of iteration, this iterator is also able to capture escaped commas where other methods struggle: const auto input = "please split,this,csv, ,line,\\,\n&quot...

When processing of captures has to be done iteratively a regex_iterator is a good choice. Dereferencing a regex_iterator returns a match_result. This is great for conditional captures or captures which have interdependence. Let's say that we want to tokenize some C++ code. Given: enum TOKENS { ...

std::vector<std::string> split(const std::string &str, std::string regex) { std::regex r{ regex }; std::sregex_token_iterator start{ str.begin(), str.end(), r, -1 }, end; return std::vector<std::string>(start, end); } split("Some string\t with whitespace &...

Let's say that we're given const string input as a phone number to be validated. We could start by requiring a numeric input with a zero or more quantifier: regex_match(input, regex("\\d*")) or a one or more quantifier: regex_match(input, regex("\\d+")) But both of those really f...

C++ provides only 4 anchors: ^ which asserts the start of the string $ which asserts the end of the string \b which asserts a \W character or the beginning or end of the string \B which asserts a \w character Let's say for example we want to capture a number with it's sign: auto input = &q...