# std::ranges::common_view<V>::base

< cpp‎ | ranges‎ | common view

constexpr V base() const& requires std::copy_constructible<V>; | (1) | (C++20 起)
constexpr V base() &&; | (2) | (C++20 起)

返回底层视图的副本。

1) 从底层视图复制构造结果。
2) 从底层视图移动构造结果。

### 参数

（无）

### 返回值

底层视图的副本。

### 示例

    #include <iostream>
    #include <ranges>
    #include <string>

    int main()
    {
        std::string str { "C++20" };
        auto view = std::views::common(str);

        std::string copy_of_str = view.base();
        std::cout << "copy of str: [" << copy_of_str << "]\n";
        std::cout << "view.base(): [" << view.base() << "]\n";

        std::string move_str = std::move(view.base());
        std::cout << "moved str:   [" << move_str << "]\n";
        std::cout << "view.base(): [" << view.base() << "]\n"; // 未指定
    }

可能的输出：

    copy of str: [C++20]
    view.base(): [C++20]
    moved str:   [C++20]
    view.base(): []