Range Adaptors

#include <ranges>
#include <vector>
#include <iostream>
#include <numeric>
int main() {
    // iota - generate sequence of values
    auto counting = std::views::iota(1, 11);  // 1 to 10
    
    // reverse - reverse iteration
    std::vector<int> v = {1, 2, 3, 4, 5};
    for (int n : v | std::views::reverse) {
        std::cout << n << " ";  // 5 4 3 2 1
    }
    std::cout << std::endl;
    
    // enumerate - get index and value (C++23, but useful to know)
    // keys/values - for associative containers
    
    // zip - combine multiple ranges (C++23)
    
    // Practical example: find first N primes
    auto is_prime = [](int n) {
        if (n < 2) return false;
        for (int i = 2; i * i <= n; ++i) {
            if (n % i == 0) return false;
        }
        return true;
    };
    
    auto primes = std::views::iota(2)
        | std::views::filter(is_prime)
        | std::views::take(10);
    
    std::cout << "First 10 primes: ";
    for (int p : primes) {
        std::cout << p << " ";
    }
    std::cout << std::endl;
    
    return 0;
}