How do I copy a vector in C++?

How do I copy a vector in C++?

You can copy a vector in C++ using the assignment operator or the copy constructor. For example:

std::vector<int> vec1 = {1, 2, 3};
std::vector<int> vec2 = vec1; // Using copy constructor

This creates a copy of vec1 in vec2.

Is there a way to copy only part of a vector?

Yes, you can use the std::vector constructor that takes iterators to copy a range. For example:

std::vector<int> partVec(vec1.begin(), vec1.begin() + 2); // Copies first two elements

What about using the assign method?

The assign method can also be used to copy elements. For example:

vec2.assign(vec1.begin(), vec1.begin() + 2); // Copies first two elements to vec2

Are there performance considerations when copying large vectors?

Yes, copying large vectors can be expensive in terms of performance. Consider using move semantics if you don't need the original vector after copying.