C++11正则表达式详解(regex_match、regex_search和regex_replace)

#include <iostream>
#include <regex>
using namespace std;
 
int main()
{
    string str;
    cin >> str;
    //\d 表示匹配数字  {4} 长度4个   \d{1，2}表示匹配数字长度为1-2
    cout << regex_match(str, regex("\\d{4}-\\d{1,2}"));
    return 0;
}

int main()
{
    string str;
    cout << "请输入邮箱：" << endl;
    while (cin >> str)//匹配邮箱
    {
        if (true == regex_match(str, regex("[a-zA-Z0-9]+@1(26|63)\\.com")))
        {
            break;
        }
        cout << "输入错误，请重新输入：" << endl;
    }
    cout << "输入成功！" << endl;
 
    return 0;
}

#include <iostream>
#include <regex>
#include <string>
using namespace std;
 
int main()
{
    string str = "hello2019-02-03word";
    smatch match;//搜索结果
    regex pattern("(\\d{4})-(\\d{1,2})-(\\d{1,2})");//搜索规则  ()表示把内容拿出来
    if (regex_search(str, match, pattern))
    {    //提取 年 月 日
        cout << "年：" << match[1] << endl;
        cout << "月：" << match[2] << endl;
        cout << "日：" << match[3] << endl;
        //下标从1开始 下标0存的是符合这个搜索规则的起始位置和结束位置
    }
    return 0;
}

#include <iostream>
#include <regex>
#include <string>
using namespace std;
 
int main()
{
    //匹配多个符合要求的字符串
    string str = "2019-08-07,2019-08-08,2019-08-09";
    smatch match;
    regex pattern("(\\d{4})-(\\d{1,2})-(\\d{1,2})");
    string::const_iterator citer = str.cbegin();
    while (regex_search(citer, str.cend(), match, pattern))//循环匹配
    {
        citer = match[0].second;
        for (size_t i = 1; i < match.size(); ++i)
        {
            cout << match[i] << " ";
        }
        cout << endl;
    }
    return 0;
}

#include <iostream>
#include <regex>
using namespace std;
int main()
{
    //替换不会修改原串
    cout << regex_replace("2019-08-07", regex("-"), "/") << endl;
    return 0;
}

int main()
{
    string str;
    cin >> str;
    cout << regex_replace(str, regex("(\\d{4})-(\\d{1,2})-(\\d{1,2})"), "$2/$3/$1");
 
    return 0;
}