View Compilation Error

0_0_34164609_12347.cpp: In function 'int main()':
0_0_34164609_12347.cpp:19:11: error: conversion from 'std::string {aka std::basic_string<char>}' to non-scalar type 'std::regex {aka std::basic_regex<char>}' requested
   regex r=s2;
           ^