template<class InputIterator, class T>
constexpr inline
InputIterator find(InputIterator first, InputIterator last, const T& val);

template<class ExecutionPolicy, class ForwardIterator,
         class T = typename iterator_traits<InputIterator>::value_type>
ForwardIterator find(ExecutionPolicy&& exec, ForwardIterator first,
                     ForwardIterator last, const T& value);

#include <iostream>
#include <numeric>
#include <string>
#include <algorithm>

int main()
{
    std::string str = "hello world!";
    auto find_it = std::find(std::begin(str), std::end(str), 'w');
    if (find_it != std::end(str))
    {
        std::cout << std::string_view(find_it, std::end(str)) << std::endl;
    }
    else
    {
        std::cout << "Нет такой буквы!" << std::endl;
    }
    return 0;
}

world!