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

(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.

Parameters

(none).

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)

Complexity

Constant.

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()));
}

See also

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

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