C++ vector size types

Question

I just started learning C++ and have a question about vectors. The book I\'m reading states that if I want to extract the size of a vector of type double (for example), I should

Answer 1

My personal feeling about this is that it is for a better code safety/readability.

For me int is a type which conveys no special meaning: it can number apples, bananas, or anything.

size_type, which is probably a typedef for size_t has a stronger meaning: it indicates a size, in bytes.

That is, it is easier to know what a variable mean. Of course, following this rationale, there could be a lot of different types for different units. But a "buffer size" is really a common case so it somehow deserves a dedicated type.

Another aspect is code maintability: if the container suddenly changes its size_type from say, uint64_t to unsigned int for instance, using size_type you don't have to change it in every source code relying on it.