Try C++23:

#include <ranges>
#include <iostream>
int main() {
    std::cout << (
        std::views::repeat("C++! "s)
        | std::views::take(3)
        | std::views::join
        | std::ranges::to<std::string>()
    ) << std::endl;
}

Output:

C++! C++! C++!