Regexp从perl转换为C++

我们有以下正则表达式来解析方程式5x+10x^3-10x^2:

[+-]?[\d(x)]*[\^\d]*

下面的代码c++,取自示例并针对任务进行修改,导致无限循环:

std::regex words_regex("[+-]?[\d(x)]*[\^\d]*");
auto words_begin = 
            std::sregex_iterator(s.begin(), s.end(), words_regex);
auto words_end = std::sregex_iterator();

for (std::sregex_iterator i = words_begin; i != words_end; ++i) {
    std::smatch match = *i;                                                 
    std::string match_str = match.str(); 
    std::cout << match_str << '\n';
}

它也会在编译时抛出警告:

1.cpp:21:35: warning: unknown escape sequence '\d' [-Wunknown-escape-sequence]
    std::regex words_regex("[+-]?[\d(x)]*[\^\d]*");
                                  ^~
1.cpp:21:43: warning: unknown escape sequence '\^' [-Wunknown-escape-sequence]
    std::regex words_regex("[+-]?[\d(x)]*[\^\d]*");
                                          ^~
1.cpp:21:45: warning: unknown escape sequence '\d' [-Wunknown-escape-sequence]
    std::regex words_regex("[+-]?[\d(x)]*[\^\d]*");

如果我们天真地将正则表达式转换为[+-]?[d(x)]*[^d]*- 无限循环离开当然.

如何正确转换正则表达式c++？

UPD:Clang版本:

Mac:concurrent macbook$ clang++ -v
Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
Target: x86_64-apple-darwin14.5.0
Thread model: posix

Jorge Israel.. 5

问题是\d尝试将其解释为转义序列,因此您必须转义反斜杠,如\\d.

另一种方法是使用原始字符串文字,如:

std::regex words_regex(R"([+-]?[\d(x)]*[\^\d]*)");

在这里看到它.

问题是\d尝试将其解释为转义序列,因此您必须转义反斜杠,如\\d.

另一种方法是使用原始字符串文字,如:

std::regex words_regex(R"([+-]?[\d(x)]*[\^\d]*)");

在这里看到它.