How do I reserve capacity and shrink-to-fit with std::span?

In C++, `std::span` is a lightweight view over a contiguous sequence of elements. However, it does not manage memory directly, as it is designed to provide a non-owning view to existing data. Therefore, operations like reserving capacity or shrinking fit do not apply directly to `std::span`, as it doesn't allocate or deallocate memory. Instead, you use containers like `std::vector` for such operations and then provide a `std::span` view over the container.

Here's an example of how to manage capacity with `std::vector` and then create a `std::span` view:


        #include 
        #include 
        #include 

        int main() {
            // Create a vector and reserve space
            std::vector vec;
            vec.reserve(10);  // Reserve capacity for 10 integers

            for (int i = 0; i < 5; ++i) {
                vec.push_back(i);  // Add elements
            }

            // Create a span from the vector
            std::span span(vec.data(), vec.size());

            std::cout << "Span size: " << span.size() << std::endl; // Output the span size

            // Shrink vector to fit its current size
            vec.shrink_to_fit(); 

            // Updating the span after shrinking
            std::span newSpan(vec.data(), vec.size());
            std::cout << "New span size after shrink: " << newSpan.size() << std::endl; // Output the new span size

            return 0;
        }

How do I reserve capacity and shrink-to-fit with std::span?

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How do I reserve capacity and shrink-to-fit with std::span?

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