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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