How do I initialize a std::vector in C++?

How do I initialize a std::vector in C++?

You can initialize a std::vector in several ways. For example, you can use the constructor with a size and default value: std::vector<int> vec(5, 0); which creates a vector of size 5 with all elements initialized to 0.

Can I initialize it with a list of values?

Yes, you can use an initializer list. For example: std::vector<int> vec = {1, 2, 3, 4, 5}; This creates a vector with those specific values.

What if I want to initialize it with another vector?

You can do that using the copy constructor. For example: std::vector<int> vec2(vec1); This creates a new vector vec2 that is a copy of vec1.

Are there any performance considerations I should be aware of?

Yes, initializing a vector with a large number of elements can be costly in terms of performance. It's often better to reserve space using vec.reserve(size) before adding elements to avoid multiple reallocations.