int main() {regex e("abc*");bool m = regex_search("abccc", e);// 输出 yescout << (m ? "yes" : "no") << endl;
}

regex e("^a.", regex_constants::grep);

int main() {string str("Email a@bc.com abc");// 等同于 match_results<string>smatch m; regex e("([[:w:]]+)@([[:w:]]+.com)");bool found = regex_search(str, m, e);// m.size=3, 存储了 3 个 resultcout << "m.size=" << m.size() << endl;/* 迭代 match_results, 输出m[0]=a@bc.com (整个匹配)m[1]=a (第1个group)m[2]=bc.com (第2个group)*/for (int n=0; n<m.size(); n++){cout << "m[" << n << "]=" << m[n].str() << endl;//等价写法 m.str(n), *(m.begin()+n) }// m.prefix=Emailcout << "m.prefix=" << m.prefix().str() << endl;// m.suffix= is minecout << "m.suffix=" << m.suffix().str() << endl;
}

int main() {string str("a@bc.com, d@ef.com, aa@b.com");regex e("([[:w:]]+)@([[:w:]]+.com)");sregex_iterator pos(str.cbegin(), str.cend(), e); // 定义 regex_iteraror// C++惯例: 默认构造的迭代器表示序列结束sregex_iterator end;/*
email=a@bc.com, user=a, domain=bc.com
email=d@ef.com, user=d, domain=ef.com
email=aa@bb.com, user=aa, domain=b.com
*/for (; pos!=end; pos++) {cout << "email=" << pos->str(0) << ", user=" << pos->str(1) << ", domain=" << pos->str(2) << endl;}
}

int main() {string str("a@bc.com, d@ef.com, aa@bb.com");regex e("([[:w:]]+)@([[:w:]]+.com)");sregex_token_iterator pos(str.cbegin(), str.cend(), e); // 定义regex_token_iteratorsregex_token_iterator end; //序列结束/*Matched: a@bc.comMatched: d@ef.comMatched: aa@bb.com*/for (; pos!=end; pos++) {cout << "Matched:  " << *pos << endl;}
}

// 第 4 个参数表示第几个 group
sregex_token_iterator pos(str.cbegin(), str.cend(), e, 2
);

int main() {string str("a bb   cd");regex e("s+"); // 匹配空格// 迭代不匹配正则表达式的部分sregex_token_iterator pos(str.cbegin(), str.cend(), e, -1);sregex_token_iterator end;/*Matched: aMatched: bbMatched: cd*/for (; pos!=end; pos++) {cout << "Matched: " << *pos << endl;}
}

int main() {string str("a@bc.com, d@ef.com, aa@bb.com");regex e("([[:w:]]+)@([[:w:]]+.com)");cout << regex_replace(str, e, "$1 is on $2");
}

a is on bc.com, d is on ef.com, aa is on bb.com