Using Standard Library Concepts

#include <concepts>
#include <iostream>
#include <string>
// Use standard concepts for clean constraints
template<std::integral T>
T double_value(T value) {
    return value * 2;
}
template<std::floating_point T>
T half_value(T value) {
    return value / 2.0;
}
// Combine concepts with &&
template<typename T>
requires std::movable<T> && std::default_initializable<T>
T create_and_move() {
    T obj{};
    return std::move(obj);
}
int main() {
    std::cout << double_value(21) << std::endl;    // 42
    std::cout << half_value(10.0) << std::endl;    // 5.0
    
    auto str = create_and_move<std::string>();
    return 0;
}