爲什麼我的C++正則表達式不起作用？

Question

好的，所以我想學習C++正則表達式，並且遇到了一些麻煩。我翻閱了代碼，至少對我來說，這是合乎邏輯的。我還使用正則表達式在線測試了它，併成功地匹配了我的字符串。前兩個（nameParser和anotherNameParser）不工作，但最後一個（sampleParser）。我真的不明白爲什麼它不驗證我的字符串。下面我包括屏幕截圖：

//http://rextester.com/tester 
//compile with g++ -std=gnu++11 main.cpp -o main 
#include <iostream> 
#include <regex> 
using namespace std; 

/* * (nameParser) 
* Beginning at the front of the string, any set of character followed by at least one or more spaces 
* followed by any set of characters with exactly one preceding dot, 
* then followed by at least one or more spaces followed by any set of characters and end of string 
*/ 

//Need the extended or basic because any version less than 4.9 doesn't fully support c++11 regular expressions (28.13). 
//The error is because creating a regex by default uses ECMAScript syntax for the expression, which doesn't support brackets. 
const regex nameParser("^[a-zA-Z]+\\s+[a-zA-Z]\\.{1}\\s+[a-zA-Z]+$",regex::extended); 
const regex anotherNameParser("[a-zA-Z]+",regex::extended); 
const regex sampleParser("(abc)"); 

int main() { 
    //simple regex testing 
    string name = "bob R. Santiago"; 
    if(regex_match(name, nameParser)) { 
     cout << "name is valid!" << endl; 
    } else cout << "Error in valdiating name!" << endl; 

    string anotherName = "Bobo"; 
    if(regex_match(anotherName, anotherNameParser)) { 
      cout << "name is valid!" << endl; 
    } else cout << "Error in valdiating name!" << endl; 

    string sample = "abc"; 
    if(regex_match(sample, sampleParser)) { 
      cout << "name is valid!" << endl; 
    } else cout << "Error in valdiating name!" << endl; 

    return 0; 
} 

Answer 1

//Need the extended or basic because gnu gcc-4.6.1 doesn't fully support c++11 regular expressions (28.13). 

它不支持他們在所有直到4.9版本，儘管<regex>報頭的存在。

有時它可能會做你想做的事，但它基本上沒有。

升級到GCC 4.9。

Answer 2

支持<regex>直到GCC 4.9才被添加。看到release notes：

運行時庫（的libstdC++）

• 爲C++ 11改進的支持，包括：
  • 爲<regex>支持;