【正则表达式1】C++11正则表达式

头文件

#include <regex>

regex_match：整个字符串是否匹配

    regex reg1("\\w+day");
    string s1 = "saturday";
    string s2 = "saturday and sunday";
    smatch r1;
    smatch r2;
    cout << boolalpha << regex_match(s1, r1, reg1) << endl;　　//true
    cout << boolalpha << regex_match(s2, r2, reg1) << endl;　　//false
    cout << "s1匹配结果：" << r1.str() << endl;　　　　　　　　　　//saturday
    cout << "s2匹配结果：" << r2.str() << endl;　　　　　　　　　　//空
    cout << endl;

regex_match：只返回第一个匹配结果

    smatch rr1;
    smatch rr2;
    cout << boolalpha << regex_search(s1, rr1, reg1) << endl;　　//true
    cout << "s1匹配结果：" << rr1.str() << endl; 　　　　　　　　　　//saturday
    cout << boolalpha << regex_search(s2, rr2, reg1) << endl;　　//true
    cout << "s1匹配结果：" << rr2.str() << endl;　　　　　　　　　　 //saturday
    cout << endl;

iterator：返回多个匹配结果

类似于指针，调用成员要用"->"

    cout << "iterator结果：" << endl;
    sregex_iterator it(s2.begin(), s2.end(), reg1);
    sregex_iterator end;
    for(; it != end; ++it)
    {
        cout << it->str() << endl;
        //cout << *it << endl; 错误
    }

    cout << "token_iterator结果：" << endl;
    sregex_token_iterator tit(s2.begin(), s2.end(), reg1);
    sregex_token_iterator tend;
    for(; tit != tend; ++tit)
    {
        cout << tit->str() << endl;
        cout << *tit << endl;
    }

子表达式匹配

    regex reg2("(\\d{1,3}):(\\d{1,3}):(\\d{1,3}):(\\d{1,3})");
    string ip = "0:11:222:333";
    smatch m; 
    regex_match(ip, m, reg2);
    cout << "输出：str()" << endl;
    cout << m.str() << endl;　　 //0:11:222:333
    cout << m.str(1) << endl;　　//0
    cout << m.str(2) << endl;　　//11
    cout << m.str(3) << endl;　　//222
    cout << m.str(4) << endl;　　//333

    cout << "输出：[i]" << endl; //结果同上
    cout << m[0] << endl;
    cout << m[1] << endl;
    cout << m[2] << endl;
    cout << m[3] << endl;
    cout << m[4] << endl;

多个匹配结果

    string ip2 = "0:11:222:333 4:55:66:7";
    sregex_iterator ip_it(ip2.begin(), ip2.end(), reg2);
    sregex_iterator ip_end;
    for(; ip_it != ip_end; ++ip_it)
    {
        cout << ip_it->str() << endl;
        cout << ip_it->str(1) << endl;
        cout << ip_it->str(2) << endl;
        cout << ip_it->str(3) << endl;
        cout << ip_it->str(4) << endl;
    }

总的程序：

#include <iostream>
#include <string>
#include <regex>
using namespace std;

int main()
{
    //regex_match匹配整个字符串
    regex reg1("\\w+day");
    string s1 = "saturday";
    string s2 = "saturday and sunday";
    smatch r1;
    smatch r2;
    cout << boolalpha << regex_match(s1, r1, reg1) << endl;
    cout << boolalpha << regex_match(s2, r2, reg1) << endl;
    cout << "s1匹配结果：" << r1.str() << endl;
    cout << "s2匹配结果：" << r2.str() << endl;
    cout << endl;

    //regex_match只返回第一个匹配结果
    smatch rr1;
    smatch rr2;
    cout << boolalpha << regex_search(s1, rr1, reg1) << endl;
    cout << "s1匹配结果：" << rr1.str() << endl;
    cout << boolalpha << regex_search(s2, rr2, reg1) << endl;
    cout << "s1匹配结果：" << rr2.str() << endl;
    cout << endl;


    //使用iterator返回多个匹配结果
    //结果要用->
    cout << "iterator结果：" << endl;
    sregex_iterator it(s2.begin(), s2.end(), reg1);
    sregex_iterator end;
    for(; it != end; ++it)
    {
        cout << it->str() << endl;
        //cout << *it << endl; 错误
    }

    cout << "token_iterator结果：" << endl;
    sregex_token_iterator tit(s2.begin(), s2.end(), reg1);
    sregex_token_iterator tend;
    for(; tit != tend; ++tit)
    {
        cout << tit->str() << endl;
        cout << *tit << endl;
    }

    //子表达式匹配
    regex reg2("(\\d{1,3}):(\\d{1,3}):(\\d{1,3}):(\\d{1,3})");
    string ip = "0:11:222:333";
    smatch m; 
    regex_match(ip, m, reg2);
    cout << "输出：str()" << endl;
    cout << m.str() << endl;
    cout << m.str(1) << endl;
    cout << m.str(2) << endl;
    cout << m.str(3) << endl;
    cout << m.str(4) << endl;

    cout << "输出：[i]" << endl;
    cout << m[0] << endl;
    cout << m[1] << endl;
    cout << m[2] << endl;
    cout << m[3] << endl;
    cout << m[4] << endl;

    //输出结果同上
    //regex_search(ip, m, str2);
    cout << endl;
    string ip2 = "0:11:222:333 4:55:66:7";
    sregex_iterator ip_it(ip2.begin(), ip2.end(), reg2);
    sregex_iterator ip_end;
    for(; ip_it != ip_end; ++ip_it)
    {
        cout << ip_it->str() << endl;
        cout << ip_it->str(1) << endl;
        cout << ip_it->str(2) << endl;
        cout << ip_it->str(3) << endl;
        cout << ip_it->str(4) << endl;
    }

    return 0;

}