问题描述
我读过几个地方,c_str()
和 data()
(在 STL 和其他实现中)的区别在于 c_str()
code> 总是空终止而 data()
不是.就我在实际实现中所见,它们要么执行相同操作,要么data()
调用 c_str()
.
I have read several places that the difference between c_str()
and data()
(in STL and other implementations) is that c_str()
is always null terminated while data()
is not.As far as I have seen in actual implementations, they either do the same or data()
calls c_str()
.
我在这里错过了什么?在哪些场景下使用哪个更正确?
What am I missing here?Which one is more correct to use in which scenarios?
推荐答案
文档是正确的.使用 c_str()
如果你想要一个空终止字符串.
The documentation is correct. Use c_str()
if you want a null terminated string.
如果实施者碰巧实施了data()
就 c_str()
而言你不必担心,如果你不需要字符串以空终止,仍然使用 data()
,在某些实现中,它可能会比 c_str() 表现得更好.
If the implementers happend to implement data()
in terms of c_str()
you don't have to worry, still use data()
if you don't need the string to be null terminated, in some implementation it may turn out to perform better than c_str().
字符串不一定必须由字符数据组成,它们可以由任何类型的元素组成.在这些情况下 data()
更有意义.c_str()
在我看来,只有当你的字符串元素是基于字符的时候才真正有用.
strings don't necessarily have to be composed of character data, they could be composed with elements of any type. In those cases data()
is more meaningful. c_str()
in my opinion is only really useful when the elements of your string are character based.
额外:从 C++11 开始,两个函数必须相同.即 data
现在需要以 null 结尾.根据cppreference:返回的数组以空值结尾,即, data() 和 c_str() 执行相同的功能."
Extra: In C++11 onwards, both functions are required to be the same. i.e. data
is now required to be null-terminated. According to cppreference: "The returned array is null-terminated, that is, data() and c_str() perform the same function."
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