C++正则匹配字符串

正则示例

以下实例使用C++正则从一串混乱的字符串中匹配带小数点的数字

点击查看代码

#include <iostream>
#include <regex>

using namespace std;

int main()
{
    smatch results;
    string str = "adbhjasdhaj1231.123QWEE QWEQWWQEDXQ 12346.4156";
    string pat("\\d+\\.\\d+");
    regex r(pat);

    // 方法1：
    for (sregex_iterator it(str.begin(), str.end(), r), end_it; it != end_it; ++it)
    {
        cout << it->str() << endl;
    }
    return 0;
}

运行后可得到以下内容：

我的C++环境参考配置教程
https://www.cnblogs.com/dapenson/p/15992769.html

封装调用示例

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#include <iostream>
#include <regex>

using namespace std;



vector<string> get_match(string str)
{
    vector<string> str_out;
    smatch results;
    string pat("\\d+\\.\\d+");
    regex r(pat);

    for (sregex_iterator it(str.begin(), str.end(), r), end_it; it != end_it; ++it)
    {
        cout << it->str() << endl;
        str_out.push_back(it->str());
    }
    return str_out;
}

int main()
{

    string str_test = "asdajsdk123123.123123dhja";
    vector<string> str_results = get_match(str_test);
    for (vector<string>::iterator iter = str_results.begin(); iter > str_results.end(); iter++)
    {
        cout << *iter << endl;
    }
    cout << str_results.size() << endl;

    return 0;
}

检查 C++ 标准编译器的版本

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#include<iostream>
using namespace std;
int main() {
    if (__cplusplus == 201703L)
        std::cout << "C++17" << endl;
    else if (__cplusplus == 201402L)
        std::cout << "C++14" << endl;
    else if (__cplusplus == 201103L)
        std::cout << "C++11" << endl;
    else if (__cplusplus == 199711L)
        std::cout << "C++98" << endl;
    else
        std::cout << "pre-standard C++" << endl;
}