std::basic_string_view<CharT,Traits>::front
Min standard notice:
Returns reference to the first character in the view. The behavior is undefined if empty() == true.
# Declarations
constexpr const_reference front() const;
(since C++17)
# Return value
Reference to the first character, equivalent to operator.
# Example
#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';
}