std :: string get（char *）而不是（const char *）
std :: string.c_str（）返回一个（const char *）值。我Googled，发现我可以做以下：
std::string.c_str() returns a (const char *) value. I Googled and found that I can do the following:
std::string myString = "Hello World";
char *buf = &myString[0];
这是怎么回事？ & myString [0] 是 std :: string 类型的对象， p>
How is this possible? &myString[0] is an object of type std::string, so how can this work?
& myString [0]std :: string
的对象。 myString [0] 是对字符串的第一个字符的引用; & myString [0] 是指向该字符的指针。运算符优先级是这样的，它表示&（myString [0]）而不是（& mystring）[0] 。
No it isn't. myString[0] is a reference to the first character of the string; &myString[0] is a pointer to that character. The operator precedence is such that it means &(myString[0]) and not (&mystring)[0].
注意，以这种方式访问，不能保证字符串将是零终止;所以如果你在一个C型函数中使用这个函数，期望一个零终止的字符串，那么你将依赖未定义的行为。
Beware that, accessed this way, there's no guarantee that the string will be zero-terminated; so if you use this in a C-style function that expects a zero-terminated string, then you'll be relying on undefined behaviour.