How do I use std::vector::reserve in C++?

What does std::vector::reserve do in C++?

std::vector::reserve is used to request a change in the capacity of a vector. It ensures that the vector can hold at least the specified number of elements without reallocating.

When should I use reserve instead of resize?

Use reserve when you want to allocate memory for future elements without changing the size of the vector. Resize, on the other hand, changes the size and initializes new elements.

Can you give me an example of using reserve?

Sure! Here's a simple example:

std::vector<int> vec;
vec.reserve(10); // reserves space for 10 integers

What happens if I reserve less than the current size?

If you reserve less than the current size, it has no effect on the vector's size or capacity. The current elements remain intact.