std::basic_string_view<CharT,Traits>::front
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< cpp | string | basic string view
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Execution control library (C++26)
std::basic_string_view
(C++20)
(C++20)
(C++23)
basic_string_view::front
Constants
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Deduction guides (C++20)
constexpr const_reference front() const;
(since C++17)
Returns reference to the first character in the view.
If empty() is true, the behavior is undefined.
(until C++26)If empty() is true:
- If the implementation is hardened, a contract violation occurs. Moreover, if the contract-violation handler returns under "observe" evaluation semantic, the behavior is undefined.
- If the implementation is not hardened, the behavior is undefined.
Contents
[edit] Return value
data_ [0]
[edit] Complexity
Constant.
[edit] Example
Run this code
#include <iostream> #include <string_view> int main() { for (std::string_view str{"ABCDEF"}; !str.empty(); str.remove_prefix(1)) std::cout << str.front() << ' ' << str << '\n'; }
Output:
A ABCDEF B BCDEF C CDEF D DEF E EF F F