std::basic_string::data

const CharT* data() const;	(1)
CharT* data();	(2)	(since C++17)

返回指向用作字符存储的基础数组的指针。指针的范围[data(); data() + size())是有效的，其中的值对应于字符串中存储的值。

The returned array is not required to be null-terminated. If empty() returns true, the pointer is a non-null pointer that should not be dereferenced.	(until C++11)
The returned array is null-terminated, that is, data() and c_str() perform the same function. If empty() returns true, the pointer points to a single null character.	(since C++11)

从data()可因下列情况而失效：

将对字符串的非Const引用传递给任何标准库函数，或

调用字符串上的非Const成员函数，不包括operator[]()，，，at()，，，front()，，，back()，，，begin()，，，end()，，，rbegin()，，，rend()...

1%29修改通过data有未定义的行为。

2%29修改存储在data()+size()有未定义的行为。

参数

%280%29

返回值

指向基础字符存储的指针。

data()i == operator for every i in [0, size()).	(until C++11)
data() + i == &operator for every i in 0, size().	(since C++11)

复杂性

常量。

例外

(none)	(until C++11)
noexcept specification: noexcept	(since C++11)

例

二次

#include <algorithm>
#include <cassert>
#include <cstring>
#include <string>
 
int main()
{
  std::string const s("Emplary");
  assert(s.size() == std::strlen(s.data()));
  assert(std::equal(s.begin(), s.end(), s.data()));
  assert(std::equal(s.data(), s.data() + s.size(), s.begin()));
  assert(0 == *(s.data() + s.size()));
}

二次

另见

front (C++11)	accesses the first character (public member function)
back (C++11)	accesses the last character (public member function)
c_str	returns a non-modifiable standard C character array version of the string (public member function)

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最后更新于：2017-12-18