# std::experimental::basic_string_view::basic_string_view

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< cpp‎ | experimental‎ | basic string view

constexpr basic_string_view(); | (1) | (library fundamentals TS)
constexpr basic_string_view(const basic_string_view& other) = default; | (2) | (library fundamentals TS)
template<class Allocator> basic_string_view(const std::basic_string<CharT, Traits, Allocator>& str); | (3) | (library fundamentals TS)
constexpr basic_string_view(const CharT* s, size_type count); | (4) | (library fundamentals TS)
constexpr basic_string_view(const CharT* s); | (5) | (library fundamentals TS)

1) Default constructor. Constructs an empty `basic_string_view`.
2) Copy constructor. Constructs a view of the same content as `other`.
3) Constructs a view of the first str.size() characters of the character array starting with the element pointed by str.data().
4) Constructs a view of the first `count` characters of the character array starting with the element pointed by `s`. `s` can contain null characters. The behavior is undefined if [s, s+count) is not a valid range (even though the constructor may not access any of the elements of this range)
5) Constructs a view of the null-terminated character string pointed to by `s`, not including the terminating null character. The length of the view is determined as if by Traits::length(s). The behavior is undefined if [s, s+Traits::length(s)) is not a valid range (even though the constructor may not access any of the elements of this range)

### Parameters

other | - | another view to initialize the view with
str | - | a C++ string object to initialize view with
s | - | pointer to a character array or a C string to initialize the view with
count | - | number of characters to include in the view

### Exceptions

1-3)
`noexcept` specification:
noexcept

### Complexity

1-4) constant

5) linear in length of `s`

### Example

Run this code

    #include <iostream>
    #include <experimental/string_view>
    int main()
    {
        std::string cppstr = "Foo";
        char array[3] = {'B', 'a', 'r'};

        std::experimental::string_view cppstr_v(cppstr);
        std::experimental::string_view array_v(array, sizeof array);

        std::experimental::wstring_view wcstr_v = L"xyzzy";

        std::cout << cppstr_v << '\n'
                  << array_v << '\n'
                  << wcstr_v.size() << '\n';
    }

Output:

    Foo
    Bar
    5

### See also

operator= | assigns a view (public member function)

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