C ++使用正则表达式搜索“正则表达式运算符”

Question

Im using regex in C++ and want regex_search * and + symbols, but it wont work, cause they are regex symbols. (using namespace std)

string s = "15 * 12";
regex rx("*");
bool flag = regex_search(s, rx);

and

terminating with uncaught exception of type std::__1::regex_error: One of *?+{ was not preceded by a valid regular expression.

How can I fix that?

Answer 1

You need to escape the special characters using '\\'. If you specify that in a c++ string constant you need to add two '\\' something like "\\*".