C++: What is std::ranges::generate (C++26)?

1#include <ranges>
2
3std::vector<int> v(10);
4
5// Generate with counter
6int counter = 0;
7std::ranges::generate(v, [&counter] { return counter++; });
8// v = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
9
10// Generate with function
11std::ranges::generate(v, [i = 0]() mutable { return i * i; });
12// v = {0, 1, 4, 9, 16, 25, 36, 49, 64, 81}
13
14// Generate Fibonacci
15std::vector<int> fib(10);
16int a = 0, b = 1;
17std::ranges::generate(fib, [&a, &b] {
18    int temp = a;
19    a = b;
20    b = temp + b;
21    return temp;
22});
23// fib = {0, 1, 1, 2, 3, 5, 8, 13, 21, 34}
24
25// Generate with index
26std::vector<int> indexed(5);
27std::ranges::generate(indexed, [i = 0]() mutable {
28    return i++ * 10;
29});
30// indexed = {0, 10, 20, 30, 40}