Does std::vector Copy Objects When Using push_back()?

Understanding std::vector's Object Copying with push_back()

In the realm of C programming, std::vector is a widely used container class for storing sequences of elements. However, a common misconception arises regarding the behavior of std::vector::push_back(): Does it copy or reference pushed objects?

Does std::vector Copy Objects on push_back() Insertion?

To answer this question, let's consider the following:

• std::vector Operates on Copies: By design, std::vector manages copies of the elements inserted into it. This means that when you push_back() an object into a std::vector, it creates a new copy within the vector's memory.
• Why Copying? The copy-on-push behavior ensures the vector's integrity and independence from the original object. The vector maintains its own copy, isolated from any subsequent modifications to the original object. This prevents pointer invalidation and memory access errors.

Storing Pointers or References in std::vector

While std::vector operates on copies by default, you can hold references or pointers to objects within it. To achieve this:

• Pointers Instead of Objects: Create a std::vector> instead of std::vector, where T represents pointers to the desired object type.
• Object Management Responsibility: When using pointers, it's crucial to ensure the longevity of the referenced objects. Utilize smart pointers (e.g., std::unique_ptr) or employ other mechanisms to prevent dangling pointers.

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