constexpr void remove_prefix( size_type n ); | (since C++17) |
Moves the start of the view forward by n characters.
The behavior is undefined if n > size().
| n | - | number of characters to remove from the start of the view |
(none).
Constant.
#include <algorithm>
#include <iostream>
#include <string_view>
using namespace std::literals;
[[nodiscard("a pure function")]]
constexpr std::size_t count_substrings(std::string_view hive, std::string_view const bee)
{
if (hive.empty() || bee.empty())
return 0U;
std::size_t buzz{};
while (bee.size() <= hive.size())
{
const auto pos = hive.find(bee);
if (pos == hive.npos)
break;
++buzz;
hive.remove_prefix(pos + bee.size());
}
return buzz;
}
int main()
{
std::string str = " trim me";
std::string_view v = str;
v.remove_prefix(std::min(v.find_first_not_of(" "), v.size()));
std::cout << "String: '" << str << "'\n"
<< "View : '" << v << "'\n";
constexpr auto hive{"bee buzz bee buzz bee"};
std::cout << "There are " << count_substrings(hive, "bee") << " bees in this hive.\n";
}Output:
String: ' trim me' View : 'trim me' There are 3 bees in this hive.
|
(C++17) | shrinks the view by moving its end backward (public member function) |
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