The following code example is taken from the book
C++20 - The Complete Guide
by Nicolai M. Josuttis,
Leanpub, 2021
The code is licensed under a
Creative Commons Attribution 4.0 International License.
// raw code
#include <iostream>
#include <string>
#include <vector>
#include <ranges>
void print(std::ranges::input_range auto&& coll)
{
int num = 0;
for (const auto& elem : coll) {
std::cout << elem << ' ';
if (++num > 30) { // print only up to 30 values:
std::cout << "...";
break;
}
}
std::cout << '\n';
}
int main()
{
std::ranges::iota_view<int> iv0; // 0 1 2 3 ...
print(iv0);
std::ranges::iota_view iv1{-2}; // -2 -1 0 1 ...
print(iv1);
std::ranges::iota_view iv2{10, 20}; // 10 11 12 ... 19
print(iv2);
auto iv3 = std::views::iota(1); // -2 -1 0 1 ...
print(iv3);
auto iv4 = std::views::iota('a', 'z'+1); // a b c ... z
print(iv4);
std::vector coll{0, 8, 15, 47, 11};
for (auto p : std::views::iota(coll.begin(), coll.end())) { // sequence of iterators
std::cout << *p << ' '; // 0 8 15 47 11
}
std::cout << '\n';
}