Namespaces
Variants
Views
Actions

std::basic_string<CharT,Traits,Allocator>::data

From cppreference.com
< cpp‎ | string‎ | basic string
 
 
 
std::basic_string
Member functions
Element access
basic_string::data
Iterators
Capacity
Operations
Search
Constants
Deduction guides (C++17)
Non-member functions
I/O
Comparison
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Numeric conversion
(C++11)(C++11)(C++11)
(C++11)(C++11)
(C++11)(C++11)(C++11)
(C++11)
(C++11)
Helper classes
 
(1)
const CharT* data() const;
(until C++11)
const CharT* data() const noexcept;
(since C++11)
(until C++20)
constexpr const CharT* data() const noexcept;
(since C++20)
(2)
CharT* data() noexcept;
(since C++17)
(until C++20)
constexpr CharT* data() noexcept;
(since C++20)

Returns a pointer to the underlying array serving as character storage. The pointer is such that the range

 [data(); data() + size()) (until C++11)
 [data(); data() + size()] (since C++11)

is valid and the values in it correspond to the values stored in the string.

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)

The pointer obtained from data() may be invalidated by:

1) Modifying the character array accessed through the const overload of data has undefined behavior.
2) Modifying the past-the-end null terminator stored at data()+size() to any value other than CharT() has undefined behavior.

Contents

[edit] Parameters

(none)

[edit] Return value

A pointer to the underlying character storage.

data()[i] == operator[](i) for every i in [0, size()).

(until C++11)

data() + i == std::addressof(operator[](i)) for every i in [0, size()].

(since C++11)

[edit] Complexity

Constant.

[edit] Example

#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()));
}

[edit] See also

(C++11)
accesses the first character
(public member function) [edit]
(C++11)
accesses the last character
(public member function) [edit]
returns a non-modifiable standard C character array version of the string
(public member function) [edit]
(C++17)
returns a pointer to the first character of a view
(public member function of std::basic_string_view<CharT,Traits>) [edit]